15 years have passed since the first publications on artificial double-negative materials and the perfect-lens concept. Since that time, research on metamaterials has been rapidly growing and has expanded well beyond materials with negative permittivity and permeability and even to areas which are far from classical electromagnetics and optics. At this time it is interesting and instructive to look back in time and think about roots of this research area. Likewise, marking this anniversary, it is the right time to think about future prospects. In this review talk we will start from reflections on some pre-cursors of current key research directions in electromagnetic metamaterials (discussing artificial chirality, extreme anisotropy, metasurfaces, etc.) and consider interesting modern implications of some of the classical ideas and results. The main body of the talk will be devoted to an overview of the present status and recent achievements in the field of electromagnetic metamaterials, with the emphasis on the results of our team. The talk will conclude with some thoughts about future research directions.
Media link(s):

Check our group web site: http://meta.aalto.fi

We demonstrate a simple, scalable fabrication method for producing large-area layered arrays of metallic nanostructures, embedded in a deformable polymer matrix. The elastomeric host medium promises active control of the material’s plasmonic and diffractive properties through dynamic tuning of the particle spacing and array geometry.

Here, we report the spatial mapping of surface plasmon polaritons (SPPs) on conical gold nano-tips by electron energy-loss spectroscopy. We observe the formation of standing wave patterns formed by reflection of plasmon modes in the apex region and use this information to deduce the local dispersion relation of the SPPs.

<p> We illustrate that the surface plasmon polariton (SPP) excitation through the prism coupling method is fundamentally limited by destructive interference of spatial light components. We propose that the destructive interference can be canceled out by tailoring the relative phase for the different spatial components. As a numerical demonstration, we show that through the phase modulation the excited SPP field is concentrated to a hot energy spot, and the SPP field intensity is dramatically enhanced about three folds in comparison with a conventional Gaussian illumination.</p>

We present an approach to fabricate single active optical antennas as well as antenna arrays consisting of semiconductor quantum dots and plasmonic nanostructures. It is based on a two-step lithographic process in combination with chemical functionalization. It allows for the deposition of QDs with high accuracy relative to arbitrary nanostructures.

Self-organized three-dimensional nanoplasmonic Bi2O3-Ag eutectic composite was obtained by the micro-pulling down method. This material exhibits localized surface plasmon resonance (LSPR) at 595 nm. To our knowledge this is the first demonstration of eutectic-based nanoplasmonic material.

<p> In this contribution, we investigate on the possibility to emulate a moving object by using a metallic reflector loaded with a linear momentum-biased metamaterial slab. It consists of an artificial dielectric whose refractive-index is modulated as a periodic function in both space and time, leading to a periodic profile of the refractive index that moves with a certain velocity. The periodicity of the spatial modulation and the modulation frequency are properly chosen in order to frequency modulate the propagating signal in the slab. We show that by properly choosing the modulation scheme of the metamaterial slab, it is possible achieving an artificial Doppler effect for static objects and compensating the Doppler frequency shift due to the real movement of the scatterers at a certain velocity, leading to the first attempt of a velocity cloak.</p>

<p> In this contribution, we propose a novel approach for the design of scattering cancellation devices operating at optical frequencies and exhibiting enhanced performance compared to the state of the art. The cloaks, consisting of an arrangement of plasmonic nanoparticles, are modeled through a 2D analytical model able to assign an average surface reactance to the nanoparticles array. The availability of a rigorous model allows us demonstrating that the use of nanoparticles with high eccentricity is able to generate a scattering cancellation effect within the entire optical range, strongly relaxing the current requirements on the nanoparticles size. Full-wave simulations confirming the desired cloaking performance of the nanoparticle-based cloaks are provided.</p>

We review our recent progress on optical invisibility cloaking in turbid optical media. This includes transient experiments, all-solid-state experimental realizations, and theoretical modeling beyond the diffusion equation.your abstract here

We show that neither sophisticated cloaking transformations nor simple compression/expansion transformations are capable of generating perfect transformation devices. This is demonstrated using simple theory and augmented by numerical simulations that investigate the role of impedance rescaling.

Nearly perfect concealing of arbitrary objects in ENZ metamaterial acting as an alignment-free cloak is proposed. The scattering suppression relies on the combination of normal and additional modes simultaneously existing in a spatially dispersive material.

Homogenization theory is often viewed as being limited to static or quasi-static low frequency, long waves and since many of the most interesting situations in structured media are at high frequencies and short waves relative to the structure it is often not used. However, it is possible, as we shall outline, to develop a high frequency homogenisation that creates dynamic effective media.

Propagation properties of periodic structures are described with the definition of the effective index for all frequencies and wavevectors. This definition is based on the complex analytic structure of the Bloch spectrum, and on an extended Kramers-Kronig expression. Several explicit formulas of the effective index will be given, for all frequencies and wavevectors, in the situations of multilayer stacks and two-dimensional photonic crystals where perturbation theory can be applied.

Sub-wavelength waveguide gratings enable the engineering of the optical properties of integrated photonic components. Sub-wavelength scale simulations over the full component are not reliable and reliance must be placed on effective media theory. It is shown here how the properties of these components may be captured by simple design rules

We examine an extraction model for metamaterials, not previously reported, that gives precise, quantitative representation of S-parameter data over the complete frequency range from DC to frequencies where the free space wavelength is only a modest factor larger than the unit cell dimension. This model is found to be the most probable model in a Bayesian analysis for several typical metamaterial unit cell designs. The model is comprised of a small number of slabs of distinct, finite thickness, one for each resonance. The resonance dispersion is Lorentzian and thus strictly causal. This new model is compared with previous models for correctness likelihood, including an appropriate Occam’s factor for each fit parameter. We find that this new model is by far the most likely to be correct in fits to S-parameter simulation data from several classic metamaterial unit cells.

Artificial diamagnetic metamaterials are known to produce impressively low permeability values in a broad frequency range. As an observable feature however, the same can be attributed to good conductors. We analyse performance of artificial diamagnetics with regards to applications such as levitation, in comparison to the use of bulk metals, and show that as long as the fields in the exterior of the body are concerned, non-structured metals outperform metamaterial structure. Furthermore, we assess the performance of practical samples of artificial diamagnetics, taking their discrete structure and finite size into account, and find important distinctions in their response as compared to the predictions of effective medium theory. Our results are therefore crucially important for the future development of this research direction.

Development of a variable index leaky wave antenna for use in localizing acoustic targets is presented. The antenna uses a one-dimensional right/left hand transmission line structure to tune the relationship between radiation angle and frequency. The antenna aperture is used to locate acoustic targets using both passive and active techniques.

We discuss our recent investigations on breaking time-reversal and spatio-temporal symmetries to provide novel functionalities in the field of metamaterials, with special emphasis on the field of acoustics and sound manipulation.

The enhancement of sound absorption by the excitation of Wood anomalies in slabs of cylindrical perforated shells is here studied. These scattering units have low losses when the diameter of the perforations is on the order of hundreds of microns or higher. It has been observed that slabs consisting of a few layers of perforated shells exhibit high levels of absorption that cannot be explained in terms of the dissipative properties of a single scatterer. This behavior is explained by the excitation of resonant Wood anomalies that redirect the sound perpendicularly to the incident direction. Thus, energy dissipation is obtained from the long path that the sound wave travels inside the slab.

We theoretically and experimentally study the acoustic scattering in a two-port one-dimensional waveguide, side-loaded by resonators. The lossless theory predicts high quality transparent modes induced by Fano interferences. In the presence of the intrinsic losses, these modes can be critically coupled leading to the coherent perfect absorption of acoustic waves. In asymmetric structures a unidirectional almost perfect absorption is possible. The control of perfect absorption by the proper tuning of few resonators and the engineering of the losses will open new possibilities in important applications in various wave-control devices.

Here we study the effect of realistic metal properties on the emergence of magnetic localized surface plasmons. These are subwavelength magnetic dipole modes supported by metallic particles that are corrugated with very long, curved grooves. By means of numerical simulations, we show that, despite the presence of losses in the metal, the concept of magnetic localized surface plasmons is general and can be applied to a broad range of frequencies, up to the mid-infrarred regime.

Inspired by the Boolean algebra, the notion of digital electronics and the binary number theory, we have developed the methodologies to “digitize” metamaterials. We explore how an arbitrary value of the permittivity function can, in principle, be synthesized by judicious combinations of only two constituent materials with two different permittivity parameters. We have analyzed the conditions upon which one can achieve such synthesis, and have investigated theoretically issues such as the role of loss, shape and dimensions of the constituent elements. Two different digital systems have been considered: (1) the “rectangular bytes” and (2) the “core-shell bytes”. We have investigated the various features of these two systems, and their advantages and constraints. We present some of our theoretical results on this concept as utilized in several case studies.

<p> Aluminum is becoming a very promising alternative to noble metals. This material is earth abundant, low in cost, CMOS compatible, and capable of supporting tunable plasmon resonances spanning the visible and UV parts of the electromagnetic spectrum. In this contribution we will explore the use of aluminum nanostructures to develop novel applications in the fields of plasmonics and metamaterials.</p>

Spin-orbit coupling enables directional scattering of light from a particle by controlling the incident polarization. We propose using polarized illumination to induce lateral scattering, associated with a lateral electromagnetic momentum, and therefore accompanied by an unusual recoil force that can be switched with the polarization, with no field gradients.

<p> Put your abstract here</p>

<p> We provide a brief introduction to supersymmetric photonics and present our newest theoretical findings and experimental results on SUSY mode conversion and the scattering dynamics of light propagating in optical SUSY partner structures. Finally, we show how these notions can be harnessed in a SUSY-inspired extension of transformation optics, enabling the substitution of high-refractive-index arrangements with low-contrast equivalent structures that exhibit identical reflection and transmission properties.</p>

Transformation optics can involve multiple transformation operations, creating confusion as to the meaning and character of these different transformations. We use an example of cloaking in curved spacetime to elucidate the difference between cloak, coordinate, and frame transformations.

We experimentally demonstrate collimation in transformation optics by designing a refractive index profile analogous to the curvature of a star. Our experiments also enable the observation of Einstein’s Rings caused by gravitational lensing as predicted in 1936.

The existence of bound states within the continuum is known since the early years of quantum mechanics. However a realistic quantum system supporting such bound states has not yet been designed. Here we present a core--shell semiconductor heterostructure composed of Hg(1-x)Cd(x)Te compounds, which is able to support the bound states within the continuum using zero-valued effective mass within the outer shell. The working principle is analogous to that of the recently proposed open core-shell plasmonic resonators for light waves.

We propose an experimental method to measure Zak phase in optical system. We can extract the property of each band gap through surface states which exists at the interface between metasurfaces and photonic crystals. By comparing the properties of two adjacent band gaps, Zak phase of the band sandwiched between them can be directly determined.

We shown that the metamaterial composed of wires of finite radius exhibit strong diamagnetic response. In previous works devoted to a wire medium it has been assumed that these structures possess only electric susceptibility, however we show that the account for the non-zero magnetic susceptibility is required for the adequate homogenization. We support analytical and numerical simulations with the experimental measurements of the scattering crosssection of the wire metamaterial block.

Bianisotropic media besides permittivity and permeability possess additional material parameters describing bianisotropic coupling. Here we consider the scenario when bianisotropic parameters are non-zero, while the permittivity and permeability tend to zero. Only a special case of reciprocal bianisotropic nihility was studied in the literature. In this work we generalize the concept of bianisotropic nihility to the case of non-reciprocal matter. We explore unique electromagnetic properties of bianisotropic nihility materials and consider their potential applications.

<p> This presentation focuses on a particular subclass of bi-isotropic metamaterials which contain non-refractive, PEMC, and simple-skewon materials as special cases. The space spanned by the three essential parameters (degrees of magneto-electricity, non-reciprocity, and impedance) will be visualized as a spherical domain.</p>

<p> A cylindrical metallic cloak working for linear surface liquid waves [Farhat et al., Phys. Rev. Lett. 101, 134501, 2008] has the ability to also control electromagnetic waves via effective anisotropic permittivity. Numerics are in good agreement with microwave experiments and confirm cloaking from 2.6 GHz to 7 GHz for transverse electric field. Moreover the field is reduced by 10 to 30 dB inside the invisibility region.</p>

We report experimental determinations of Zak phase in one-dimensional phononic crystals. Band inversion and topological transition are identified. We use two methods to experimentally determine the Zak phase for the second bands. Interface states are observed at the interfaces separating two phononic crystals with different topological characteristics.

<p> We find scattering cancellation in diffusive transport of acoustics waves propagating through strongly scattering media and for ballistic sound in the long wavelength limit.</p>

By creating two or more resonances on a structured thin membrane, it can be shown that a reflecting surface placed close by can cause the two neighboring resonances to hybridize at a frequency intermediate between the two. As the hybrid resonance’s wave amplitude profile is necessarily the linear superposition of the two original resonant eigenfunctions, the two degrees of freedom can mean that the surface-averaged hybrid resonance amplitude, and its variance, may be separately tunable. It is shown that whereas the average amplitude can serve to match impedance with air, the variance component is “deaf” and serves to absorb the incoming wave energy. The result is a deeply subwavelength structure that can totally absorb the incident wave at tunable frequencies.

In this work, gain enhancement of a metamaterial lens-horn antenna is shown when a fishnet lens is coupled to the horn’s aperture. The gain enhancement occurs in a narrow bandwidth corresponding to the Extraordinary Transmission (ET) resonance. These results demonstrate the feasibility to design smaller antennas with identical or even better radiation characteristics than standard horn antennas. Our design achieves a profiled reduction factor as high as 74% compared to a standard horn, with a gain of 15.8 dB.

A four-vector field based formulation suitable for a special class of bianisotropic media is presented and advantages/drawbacks are discussed. It is shown the four-vector approach (compared to the known six-vector formalism) can offer enhanced physical insight and mathematical simplification due to reduced dimensionality. The Green’s functions of a parallel-plate waveguide filled with uniaxial electric and magnetic material is found to demonstrate the implementation of the four-vector approach. Future work is also discussed.

We propose new type of temaperature tunable metamaterial based on semicon- ductor superlattice for THz applications. We have analyzed that the shape and topology of equal frequency contours depending on the external temperature. It was shown that transition from elliptical to hyperbolic regime, so called ”topological transition”, can be observed at room temperature.

Performance improvement of a planar antenna array system has been proposed, focused in give a solution to novel satellite applications. The need of low profile, high gain antenna with strict constraints make of this an excellent challenge where apply metamaterial approach. Simulation results has been compared with radiation measurements.

<p> We present a tunable metamaterial antenna using RF-MEMS (radio micro-electromechanical systems), based on a parallel-plate capacitor within a CRLH-TL structure (composite right-left hand transmission line), which can be used as a sensor. The device is compatible with micromachining fabrication processes, and it is based on electrostatic actuation.</p>

In this paper, a transparent metamaterial (MTM) absorber in dual band application is proposed. The absorber is designed using on indium tin oxide (ITO) film for transparency. The unit cell of the proposed absorber consists of an electric LC (ELC) resonator and a ground plate, which are printed on opposite sides of the glass substrate. The ELC resonator comprises two symmetric triangular split ring resonators (TSRRs) for 8 GHz band and another two symmetric TSRRs for 12 GHz band.

In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system - magnetized plasma.
Media link(s):

 

arXiv:1410.4596

 

 

Discontinuities in the geometry of a beam pipe can represent serious issues for the stability of the beam in a particle accelerator. Many devices installed along the machine introduce parasitic cavities which are undesired and give rise to wake fields and resonances, which on turn contribute in de-stabilizing the beam. These resonances are often damped using dispersive or resistive materials placed in specific points in the cavity. This paper analyzes numerically the possibility to use of simple metamaterial insertions to perform the mode damping.

We investigate Second Harmonic Generation in the context of extraordinary optical transmission. We show that the radiation pattern and the transmission efficiency of second harmonic light in metallic arrays of rectangular holes strongly depends on the electromagnetic modes excited at both the fundamental and second harmonic frequencies. Second harmonic generation is constrained by the spatial distribution of these fields and their ability to couple with radiation. In particular, the symmetry properties of the second harmonic fields are crucial in the near-to-far field coupling process. For instance, we show how light generated at second harmonic can excite electromagnetic modes otherwise inaccessible in the linear regime under normal incidence illumination. By reciprocity, these modes can only couple to off-normal diffraction orders in the lattice. Finally, we demonstrate that the existence of dark surface plasmons at the fundamental field can be identified through a non-invasive method, which is precisely based on the singular symmetry properties of second harmonic.

We develop a model for the coupling of leaky eigenmodes in meta-molecules The results show a good agreement with full-wave simulations. This model provides interesting physical insights on the coupling scheme and pave the way for the design and optimization of resonances in more complicated systems.

The conventional grating consisting of a periodic distribution of transmission slits made in a thick metal slab is modified by adding grooves at both sides of the metal slab in order to introduce transmission zeros below and above the Fabry-Perot transmission bands thus improving frequency selectivity. The analysis of this structure is carried out using an analytical model that involves transmission lines and lumped circuit elements. The values of the electrical parameters of the model can be obtained in closed form. Numerical results provided by finite-elements simulations are used to check the validity of the model and to illustrate the applications of the proposed structure

We retrieve the full polarizability tensor of an infinitely long cylinder illuminated by plane waves under oblique incidence. Two mathematically equivalent representations of the tensor are obtained: a diagonal form when the polarizations of the impinging light are considered separately, and a non-diagonal form when polarizations are combined. This interconvertibility reveals the precise physical origins of the predicted magneto-electric coupling, being a necessary consequence of the difference in the scattering of transverse electric and transverse magnetic polarizations. All quantitative and qualitative properties of the magneto-electric coupling can be traced to this simple difference, such as its unusual scaling and symmetry properties.

An all-dielectric multilayer polarization converter based on form birefringence is analytically synthesized and designed at microwave frequencies. Form birefringence enables to independently control the transmission characteristics of the parallel and perpendicular components of a linearly polarized incident plane-wave, thus achieving polarization conversion. The performance of the converter is demonstrated using 3D full wave simulations proving an axial ratio lower than 3 dB within the X-band whilst offering good angular stability.

Spin-polarized one-way transport has been proposed and demonstrated in time-reversal invariant photonic topological insulators, where the pseudo-spin is locked to the linear momentum. These pseudospin states are carried in the carefully designed photonic crystals or metamaterials that are usually difficult to fabricate. Here, we propose and experimentally demonstrate a spin-filtered waveguide without using any bulk material. The pseudospin is enforced simply by imposing boundary conditions. Wave propagation in the waveguide is robust against deformations that do not induce spin flip.

We report the design, simulation and measurement of a quad helix metamaterial absorber that works for a wider range of wavelengths and independent to changes in the polarization of the incident light. FDTD method is used for the modeling of the design. From the obtained results, it can be state that the proposed design shows an average absorbance of 87.48% in the wavelength range of 300 to 1700 nm and an absorption peak of 96.6% at 350 nm. The polarization independence property can be explained by circular dichroism exhibited by the helices. Systematic study of the changes in absorption efficiency with variations in the geometric parameters is also carried out.

Loading an electrically small antenna (ESA) with non-Foster active matching networks (MN) is an interesting way to obtain broad impedance bandwidth. Locating one of these active networks in the antenna structure itself can be advantageous for compact designs. The introduction of the so called sensitivity (Sens) parameter allows finding a suitable placement for the MN. Some radiation considerations can be described, according to the antenna plus MN topology chosen at a low sensitivity point.

A theoretical analysis of an annular ring microstrip antenna with metamaterial substrate is presented. The approach is based on the cavity model. By including in the substrate a conventional dielectric material and a metamaterial possessing negative permittivity and permeability, a frequency independent resonance condition is found over a continuous band of frequencies.

We propose the concept of generalized hyperbolic metamaterials (GHMMs) composed of anisotropic slabs. We develop effective medium theory for layered GHMMs and show that it is possible to obtain any sign combination on the diagonal of the effective medium permittivity tensor.

The effective properties of a perpendicularly magnetized two-dimensional antidot lattice having periodicity and hole size in the nanometric range are studied. The effective rules involving the effective wavelength and the effective wave vector of collective modes characterize these magnonic crystals as magnonic metamaterials.

<p> We discuss a general and compact first-principles effective medium theory, based on a multiscale approach, for describing the homogenized electromagnetic response of a periodic metamaterial. As an intriguing and unexpected result, we prove that electromagnetic chirality can occur in 1D periodic composites whose inclusions are achiral.</p>

In this paper, we propose a chiral metamaterial structure that enables a dual-band 90° polarization rotator effect. The bilayered chiral metamaterial is composed by twist different size “V” antenna resonators in four-fold rotation symmetry. Analysis also shows such asymmetric twist structure can be attributed to the induced asymmetric transmission that support strong optical activity.

We demonstrate a novel type of mirror, which reflects one circular polarization without reversing its handedness, while being a perfect absorber for the other circular polarization. This ultimate 2D-chiral effect enables circularly polarized cavities and lasers as well as novel spectroscopic techniques.

Enhanced performance of new metamaterial(MTM) loaded, CoplanarWaveguide(CPW) fed miniaturized Square Fractal Antenna(SFA) is reported. Design and simulation were performed using HFSS simulation software. Proposed antenna size is 23mmx23mm on FR4 substrate. SFA resonates at triple frequencies whereas metamaterial antenna resonates at four frequencies with improved gain and more focused radiation.

This paper presents simulation results of two different subwavelength metamaterial-based antireflection coatings operating at millimeter waves. The first design minimizes the reflection from a slab of acrylic and the second design minimizes the reflection from a slab of human tissue comprising skin-blood-skin layers. These designs achieve a relative reduction in the reflected power by 99.5% (23 dB) and 99.9% (35 dB), respectively, at 60 GHz. The overall transmitted power is enhanced by up to 39%, limited by the inherent losses in the tissues.

We present computationally intensive electromagnetic analysis of metamaterials involving deformed nanowires. Random deformations are introduced to modify perfect nanowires in order to investigate the effect of geometric deviations on scattering properties of optical metamaterials. Numerical simulations of realistic structures of finite extent are performed accurately and efficiently using a rigorous simulation environment based on surface formulations and the multilevel fast multipole algorithm (MLFMA). Statistically common results of deformations, such as forward-scattering enhancements, are demonstrated on realistic metamaterial models.

A flat, metamaterial lens was designed for millimetre waves. A system with a pair of these lenses placed on either side of biological tissue, consisting of a 2-layer skin-blood structure, was simulated. The directivity was enhanced by 9.5 dB compared to the case without the lenses.

Based on a renewed Jones formalism, we study single or stacked metallic metamaterials for the terahertz domain. This allows us to theoretically investigate with a simple and analytical model several polarization applications such as the design of half-wave plates an polarization converters, and a new formulation of the Malus Law for metallic polarizers.

We fabricated and investigated micrometer-sized, three-dimensional chiral meta-molecules (CMMs) of ferromagnetic metal, permalloy. The angle-resolving measurement showed that a resonance at a lower magnetic field did not shift, while another resonances shifted significantly depending on the direction of the magnetic field. Possible origins of these resonance were discussed.

3D printing technology provides the precise fabrication for complicated structure which cannot be realizable in the past. With this noble technology, we can make sophisticated metamaterials in the microwave regime. By transformation optics and effective medium theory, we designed isotropic and graded index lens which collimates the TE spherical wave. Our design technique optimizes values of permittivity which can be realized by 3D printing.

The emergence of the self-modulation instability of monochromatic microwave spin waves excited in a periodic magnetic film structure, a magnetic metamaterial – magnonic crystal, has been observed. The magnonic crystal was fabricated by chemically etching the surface a single-crystal yttrium–iron garnet film. The self-modulation instability has been observed at the frequencies corresponding to the band gaps of the spin-wave spectrum of the magnonic crystal caused by Bragg resonances.

We propose a metal-insulator-metal (MIM) structure that enhances absorption and emission process of lanthanide upconversion simultaneously. The MIM structure consists of metal strips on the thin upconversion material layer coated on the metal substrate. Two plasmonic MIM modes can enhance absorption and emission process, respectively. Therefore, the efficiency of the upconversion can be greatly increased by resonant absorption and spontaneous emission rate enhancement.

Put your abstract here Two metamaterial based satellite navigation terminal antennas are proposed in this paper. One is multi-frequency RHCP microstrip antenna, the other is a half-mode cavity backed SIW RHCP antenna. The RIS and CSRR are used to improve antenna performance and diminish antenna size.

A broadband high gain planar meta-material based Resonant Cavity Antenna (RCA) is proposed operating at C-band. The RCA is modelled using simple ray tracing method. The unit cell metamaterial consists of Artificial Magnetic Conductor (AMC) and square patch laminated on either side of low loss commercial dielectric material of dielectric constant 2.4 & thickness 0.813mm, is used as the superstrate to designed RCA. Square patch is capacitive type and that AMC as inductive. Effects of the reflection phase of the substrate decides the high gain of the antenna. A cylindrical dielectric resonator antenna (CDRA) has been used as the primary radiator. The metamaterial unit cell structure is characterized and its effective material parameters showing meta-material characteristics are extracted through its S-parameters simulation. The proposed antenna achieves 22.4dBi gain with 2 layers of 4x4 array superstrate with bandwidth of around 2.8GHz. The proposed 2 layer structure will be optimized for height of the cavity using Particle Swam Optimization technique, whose result will be published at the conference.

We study magneto-chiral (MCh) effects for the X-band microwaves by a single metamolecule consisting of a copper chiral structure and ferrite rod. The nonreciprocal differences in refractive indices are evaluated to be 10^{-3} at 200mT, which are much larger than those by MCh effects of natural chiral molecules.

We propose a method to dynamically control electromagnetically induced transparency like effect in a metamaterial by conductivity modulation for the storage of electromagnetic waves. The storage and retrieval of electromagnetic waves are experimentally demonstrated in microwave region using the metamaterial loaded with switching diodes.

We report on the experimental results of the third-harmonic generation spectroscopy of silicon nanodisks excited at their electric and magnetic dipolar resonances. Efficient third-harmonic generation enhanced by the magnetic response of the nanodisks is observed, whereas the electric dipolar resonance yields less nonlinear conversion, which is explained by the lower penetration depth of the up-converted radiation into silicon.

In this study, by using a non-linear recursive feedback optical-thermodynamic numerical analysis we show that optical absorption induced temperature change could affect the permittivity of metal and thus diminish the efficiency of metamaterial absorber.

We investigate the applicability of the point electric and magnetic dipoles approximation to dielectric meta-atoms on an example of the dielectric ring metamaterial. Despite large electrical size of the high-dielectric meta-atoms, the dipole approximation allows for prediction of the metamaterials properties well for the rings diameter up to approximately 0.8 of the lattice constant.

In this paper we apply the framework of temporal coupled-mode theory on the case of resonant transmission line (TL) consisting of microstrip line coupled to split-ring resonators (SRR). In particular, we study the system which breaks the mirror symmetry by moving the slit in the SRR. The combination of two such SRRs in anti-symmetric configuration is shown to posses two orthogonal resonant modes which both couple to the line with controllable coupling strengths and corresponding Q-factors. Such an approach could prove to be useful in microstrip filter design, classical electromagnetically induced transparency (EIT) and slow wave structures.

In this paper we have investigated the performance of a microstrip patch antenna using square Two-dimensional EBG structure. The EBG structure is used as substrate and superstrate. The proposed Antenna is designed at an operating resonant frequency of 4.65GHz covering the band of WLAN applications. From the comparison of three different configurations of patch antenna with homogeneous substrate, with EBG substrate and with EBG substrate and superstrate, it is shown that performance of the patch antenna is enhanced with the use of EBG substrate as well as with superstrate. The simulation has been performed using CST Microwave Studio Suite.

The behavior of electrothermally controlled metamaterials, when implemented with different bias networks, is investigated in this paper. The proposed devices obtained from the combination of electrothermal actuators with an SRR can be actuated by employing two discrete topologies of the bias lines. These components exhibit MNG as well as DNG performance, along with bandwidth tunability.

We present a novel framework for the analysis and engineering of light enhancement in disordered metamaterials. This framework exploits interactions between resonators. Despite Ohmic losses which tend to suppress interactions, we show that intense light confinement can be achieved in optical plasmonic metamaterials. This framework shows excellent agreement with experimental observations.

<p> We study the steady-state lasing of the laser that contains anisotropic and gyrotropic layers and the active medium with linear anisotropy. We demonstrate that in the laser observed PT-symmetry breaking in polarization space. PT-symmetry breaking results to suppression of lasing.</p>

<p> A compact ultra wide band impedances transformer based on new configuration of composite right/left handed transmission line is presented. The proposed design introduces ultra wide band pass frequencies extended from 2 GHz up to 11 GHz with perfect matching transmission coefficient. However, the whole topology is designed using new loaded inductor configuration of CRLH. This L-CRLH is implemented using loaded inductor to construct shunt tank of gap capacitor and strip inductor, and shunt tank formed using patch capacitor with shorted strip inductor. Furthermore, the paper present analytical study, equivalent circuit model, 3D fall wave simulation and fabrication measurement results. The results shows perfect insertion losses equal 0.2 dB and return losses reach to 19 dB within extended band pass band from 3 GHz up to 12 GHz. Moreover, it introduces very compact size equal 2.7×8.6 mm2 (58% size reduction compared to single frequency /4 transformer)</p>

Knowledge-Based System is a tool that: contains all relationships between all variables of the object; allows to calculate the values of one part of variables through others; allows to solve direct and inverse problems.

<p> This paper exhibits a new compact high selective gap bandpass filter designed for the 5 GHz WiMAX service. The filter is based on four order coupling of coupled gap composite right left handed transmission line resonators. The composite right left handed resonators is designed to demonstrate a zeroth order mode at the passband center frequency (5.25 GHz) for filter size reduction. The filter has a compact size 20×20mm2. The design concepts of the coupled cell and the whole filter response are discussed and verified using full electromagnetic full wave simulations and confirmed by experimental measurements. The results</p>

We investigate the eigenmodes of both ultrathin quadrifilar spirals and ensembles made up of such spirals by comparing experimental near-field scans with numerical finite-element models. These modes can be understood in the picture of electric and magnetic localized spoof plasmons.

Different methods based on Electromagnetic Band-Gap materials are used to enhance the directivity of dipoles with a back reflector and compared. The EBG media consist of a periodic arrangement of dielectric cylinders that are excited either inside or at the edge of the band-gap by a half-wavelength dipole, while a ground plane with finite size acts as a reflector against backscattering. Strengths and weaknesses of the two methods are assessed considering both square and triangular lattices.

We show that localized plasmon resonances of single metal nanoparticle and nanohole or their two dimensional arrays fabricated in the vicinity of an ITO surface can be efficiently tuned by an electrostatic field. Results of our theoretical analysis and computer simulation show that the shift of plasmon resonance frequency is about several tens of nanometers that is comparable with a width of the resonance.

Multi-band or broadband power absorption has been obtained from multiple arrangements of split cut wires (SCWs) of different length on grounded dielectric substrate. Computational tools were used to model the interaction between electromagnetic waves and materials with the SCWs structure. The multi-resonance of SCWs is found to be greatly dependent on substrate materials (FR4, air). Insertion of an air layer at the bottom side of the ground plane has the effect of broadening the absorption band, due to the effect of increasing the dielectric resistance by increasing substrate thickness and by decreasing effective permittivity. For the multi-resonance structure of 13 SCWs, a broad bandwidth (6.3-7.6 GHz with respect to 80% absorbance) is predicted. The simulation result is in good agreement with experimental result measured by free space method.

<p> In this paper, two novel ultra wideband (UWB) minimized metamaterial antennas based on the composite right/left-handed transmission line (CRLH-TL) structures are designed.Overall sizes of the CRLH antennas are 24.8mm by 9.5mm by 1.6mm and 37.2mm by 9.25mm by 1.6mm, respectively.</p>

Metamaterial inspired unit cells like CRLH and SRR has been used to realize microwave filter in microstrip and waveguide systems respectively. CRLH based filter designed at 2.45 GHz provides an insertion loss of 1.6 dB with harmonic suppression up to 10 GHz with 67% size reduction when compared with a conventional edge-coupled band-pass filter designed around the same frequency. One dimensional (1-D) SRR matrix loaded in a waveguide shows the possibility of realizing a stop-band with sharp notch in the pass-band and stop-band in the pass-band of normal rectangular waveguide with tailoring of the dimensions of SRR unit cells.

The possibility is shown and conditions are obtained for creation of epsilon-near-zero fishnet metamaterials based on the multilayered metal-dielectric nanostructure with implemented metallic nanocylinders. It is established the possibility of realization of diffraction-free and low-loss regime of light beam propagation in these media.

The features are considered of the excitation of Bessel plasmon polaritons at the boundary of a hyperbolic absorbing metamaterial with near zero permittivity that is based on the dielectric matrix with metal nanorods embedded into it orthogonally to the surface. The possibility is shown and the conditions are determined of the changes of radial energy flux direction in the Bessel plasmon polaritons excited on the surface of "isotropic medium - hyperbolic metamaterial."

<p> Experimentally demonstrated the influence of electron magnetic resonance in ferrite on the nonlinear properties of meta-atoms. Experimentally demonstrated the possibility of the resonant tuning the resonant frequency of SRR loaded with ferrite using the microwave power and magnetic field. Shown that when the magnetic field reaches a certain magnitude, the nonlinearity of meta-atom increases and the resonance curve becomes disturbed and demonstrates a multistability.</p>

We experimentally investigated the role of background signal in time resolved photoluminescence experiments with single quantum dots on substrates, acting as a hot-spot enabling the plasmon supported fluorescence enhancement of gold.

<p> Here we show a novel design of a dual-band second-order bandpass filter, with two transmission zeros between pass bands. Filter is designed combining resonances of two ENZ waveguides, which are connected in parallel between standard rectangular waveguides. Filter is simulated and optimized using mode matching (MM) and finite elements (FEM) techniques. Dual-band filter has passbands at 8 GHz and 11.9 GHz, with bandwidth of 155 MHz and 355 MHz, insertion loss of 1.6 dB and 0.8 dB, and in-band return loss of 21 dB and 18 dB respectively.</p>

We demonstrate the transmissive terahertz metasurfaces can be achieved by the proposed Babinet crosslink meta-atoms (BCMs) with extremely higher aperture ratio in comparison to the conventional meta-cavity structures. The proposed BCMs can manipulate their transmission spectral properties as similar as the conventional meta-cavities but also achieve high transparency at the same time in other frequencies even for visible range.

Refractive index can be used in case of metamaterials but not in case of metasurfaces. We propose new optical properties for metasurfaces, easily retrievable from transmission/reflection data, which are unique, unlike refractive index which depends on the thickness of the effective medium, and can be used to easily determine the imaging properties of optical metasurfaces. It is also shown that anomalous refraction can be observed on non-gradient metasurfaces as well as on gradient ones.

We experimentally demonstrate a concomitant deep-subwavelength near-field imaging of the electric and magnetic intensities of the optical modes localized in a photonic crystal nanocavity, by exploiting the electric and magnetic polarizability components of a plasmonic near-field probe along with the perturbation imaging method.

A circularly polarized patch antenna loaded with metamaterial is presented. The antenna is designed with a truncated corner square patch placed between periodic metal plates and the ground plane. The antenna with a size of 32 mm × 32 mm × 3 mm resulted in an impedance bandwidth of 4.7–7.48 GHz and an AR bandwidth of 4.9–6.2 GHz.

A novel tunable filter based on ENZ waveguide technology is presented and discussed. This kind of filter utilizes the possibility of independent tuning of two types of resonances that occur in ENZ waveguides using short slot cuts in the ENZ channels. By forming a dual-channel configuration, a second-order bandpass filter can be obtained using zeroorder- resonance (ZOR) from one channel and Fabry-Perot (FP) resonance from the other one (whose frequency is slightly different from ZOR). Both resonances can be simultaneously and equally tuned by changing the respective slots’ lengths. The maximum observed passband shift is 900 MHz or 8.3%. During filter tuning, 3 dB-bandwidth varies between 330 MHz (3.4%) and 470 MHz (4.4%) as the length of the tuning slots decreases. Maximum insertion loss observed is 1.8 dB.

We present an ultra-wideband metamaterial absorber with active frequency selective surface (AFSS). The metamaterial absorber achieves three absorbing bands at different frequencies and has wideband absorption with a reflectivity below -8 dB over the range from 2.43 GHz to 14 GHz.

In this work, a band-pass plasmonic filter composed of a traditional microstrip line and a gradient metallic strip drilled with subwavelength holes is proposed. Numerical simulations on the S-parameters demonstrate the good performance in the pass band. This kind of plasmonic filter poses potential applications in developing advanced plasmonic integrated circuits in the microwave and terahertz frequencies.

A new design approach to a small band-pass filter based on Composite Right/Left-Handed (CRLH-TL) transmission lines for the target Terrestrial-Digital Multimedia Broadcasting (T-DMB, 174-216 MHz) band-pass filtering, which is a digital radio transmission technology developed in South Korea. The overall size of the proposed filter is substantially diminished compared to similar filters reported recently, and unwanted passbands are effectively suppressed. For the verification of this approach, the experimental results are demonstrated along with full-wave simulation and equivalent circuit simulation results.

The dynamic domain wall behaviour of a thin permalloy ring is investigated in the presence of RF fields using numerical simulations. Our results reveal an intrinsic linear oscillation of the domain walls following low-strength pulse excitation and regions of strongly non-linear oscillatory behaviour when increasing pulse strength.

<p> This paper introduces a new compact triple band left handed antenna. Applying a composite right left handed transmission line, and open circuit termination load, the antenna operates at triple band frequencies, 1.8 GHz, 3.5 GHz and 5.8 GHz with total size 21×25 mm2 (only 27% compared to conventional microstrip antenna). A compromise between the proposed antenna's compact size and efficiency is made, as a result the antenna provides a maximum directive gain equals 1.37 dBi, 2.76 dBi and 3.61 dBi, respectively. The proposed antenna can serve WiMAX and GSM applications efficiently. The antenna performance is validated by full wave simulation and experimental measurements.</p>

Metamaterials represent a new paradigm in electromagnetic science and technology. They have already leaded to many unprecedented microwave applications, which may be classified in three categories: guided-wave, radiated-wave and refracted-wave applications. Control and manipulation of electromagnetic waves is at the heart of many industries from wireless communication, Internet and optical data storage to imaging and displays. Progress in these technologies places challenging demands on material properties and therefore structured electromagnetic materials. Metamaterials are a special class of structured materials. In this paper, harmonics resonance frequency of embedded composite right / left handed transmission line (CRLH-TL) array has been introduced. The analysis and investigation are done by a commercial software. The good agreement between the theoretical expectation and the simulation results is observed. Finally, the application of the proposed CRLH-TL array was examined in microstrip antenna design. The proposed microstrip antenna structure has been fabricated and the measured S-parameters of the proposed structure can be analyzed with network analyzer to demonstrate the excellent performance and satisfy multiband frequencies using conventional single microstrip patch antenna.

<p> We reveal and study the topological transition in a metamaterial formed by parallel nanowires of polaritonic material. When the dispersion transits from the elliptic (epsilon-positive) to hyperbolic (epsilon-indefinite) regime, a very specific isofrequency surface arises which implies an extraordinary Purcell factor in spite of noticeable optical losses.</p>

A simple band-notched coplanar waveguide (BNCPW) is presented in this paper, which is designed based on the idea that a defect mode in the bandgap between the fundamental and higher modes of the spoof surface plasmon polaritons (SSPPs) can be introduced to form a stopband. By properly tuning the geometrical parameters of the strips, we can introduce a very narrow stopband at will in the working band of the CPW.

We present a transformation-optics meta-lens, which is made of inhomogeneous isotropic dielectric, and experimentally demonstrate the high-resolution imaging meta-lens in the microwave frequencies. The lens is realized by non-resonant metamaterials, which are fabricated with multilayered dielectric plates by drilling inhomogeneous air holes. We validate the high-resolution imaging performance and magnification factor in experiment.

The paper presents a new negative refractive index (NRI) metamaterial unit cell structure. The unit cell displays the negative refractive index properties in the S-band, C-band, X-band and Ku-band of microwave region. The unit cell also exhibits these negative refractive index properties with maximum 1.71 GHz wideband bandwidth in the microwave spectra. It is a promising design for its wideband and multi-band NRI operation in the electromagnetic paradigm.

It is shown that in a lossless and in-plane saturated ferromagnetic film the dynamic permeability is negative for frequencies corresponding to the backward volume spin waves. The electromagnetic radiation can be coupled to that of backward spin waves and the ferromagnetic film behaves as a magnetic metamaterial with negative permeability.

An interplay between elements in the planar magnetic metamaterial was investigated. Using recently elaborated dipole-exchange spin-wave theory for finite-width magnetic waveguide the relation between inter-element interaction and periodic structure parameters was obtained analytically. The spin-wave spectrum in such structure was calculated in the presence of an arbitrary directed external bias magnetic field.

Whispering gallery modes (WGMs) have ultra-high quality factor but only non-directional light emission property. We suggest a novel way to restore WGM in resonant cavity of deformed boundary shape with Transformation optics. Conformal mapping make it possible with only density controlled isotropic material. FEM and microwave near-field scanning result prove that our idea is working. It is expected to be applied to wide range of optical cavity.

A novel approach to tuneable, passive, reciprocal reactances is devised and applied to a basic composite right left handed metamaterial transmission line at UHF frequencies. A tuneable inductance rather than capacitance is chosen as exemplary circuit, highlighting some of the additional degrees-of-freedom for tuneable unit cells and RF devices composed thereof.

We present a plasmonic metamaterial exhibiting a resonant enhancement of the lowest order toroidal multipole at the second harmonic. The optical spectra at the fundamental frequency (FF) show that the enhanced nonlinear optical response of the toroidal metamaterial is due to an excitation of an electromagnetic resonance at the FF.

This work proposes a metamaterial reflector lens antenna operating in Ku band. The lens antenna is made up of omega shaped metamaterial and the parabolic reflector made up of PEC. The simulation is carried out using CST MWS. The simulation results show very good far-field properties and a high gain up to 24.1dBi is achieved.

Wireless power transfer systems using realy coils are equivalent to one and two dimensional magnetoinductive waveguides. Useful insights may be gained by considering the properties of these waves in the context of such systems. Standing wave effects dominate multi-point power transfer strategies and limit the efficiency. Simple methods to alleviate thee problems are described.

We consider a cut-wire metamaterial as a harvester of ambient electromagnetic energy within the S band. The efficiency of the metamaterial energy harvester can be increased up to 30 % by adding a nonlinear element. An equivalent electrical circuit model is constructed for the purpose of optimizing the design.

Missiles and fighter jets that travel at a speed much higher than the speed of sound experience highly elevated temperatures due to air friction. Conventional anti-reflection coating designs based on heterogeneous materials may not be well suited to these applications as a variety of temperature-induced problems degrade the anti-reflection performance and the structural integrity. Here, authors show that a dielectric-based anisotropic metamaterial slab can serve as an effective, broadband anti-reflection layer for microwaves.

After the metamaterial hype [Palikaras et al., 2014 8th International Congress, 2014, 397] there is a huge interest for metamaterials at a reasonable price. Colloidal synthesis methods and colloidal self-assembly methods can accept this challenge. We report about the concept of substrate-supported nanoparticles overgrowth and template-assisted colloidal self-assembly of nanoparticles to achieve local and propagating magnetic resonances on the centimeter scale.

<p> We investigate the conditions for the emergence of wave instabilities in a vacuum cavity delimited by two plasmonic cylinders in relative rotation. We show that for a small air gap thickness and for rotation velocities above a certain threshold, the interaction between the surface plasmons of the individual cylinders gives rise to wave instabilities. The instabilities are observed only for certain modes of oscillation and are due to the transformation of kinetic energy into electromagnetic energy.</p>

<p> We show experimentally a 4-fold reduction of the intensity required to achieve sub-diffraction resolution in a stimulated-emission-depletion (STED) microscope, in good agreement with theory. This shows that the theoretical prediction of a 100-fold intensity-reduction is achievable.</p>

Loops of two metallic or semiconductor materials were used by Thomas Seebeck nearly two centuries ago in his discovery of the thermoelectric effect. Replacing the lamp in this seminal experiment by an ultrashort laser and scaling down the loop to the nanoscale is predicted to lead to a magnetic pulse with high confinement in time and space. Here we investigate how characteristics of the light pulse and the nanoring influence the generation of the magnetic pulse.

Most metamaterials (MMs) to date are made with metallic constituents, resulting in significant dissipation loss in the optical domain. Therefore, we need to find other ways to create high-quality resonators with less dissipative loss for the meta-atoms. One innovative approach we plan is to reduce dissipative losses by making use of dielectrics rather than metals for building the EM resonators. This avoids resonant loss in the metals and we indeed demonstrate electric and magnetic dielectric metamaterial resonators with very large quality factors. The resulting structures can be straightforwardly scaled at optical frequencies to create low-loss MMs with a wide range of properties.

<p> Atomically thin materials, such as graphene and transition metal dichalcogenides, offer an interesting platform to tailor nanoscale light-matter interaction. The ease with which these materials can be incorporated into optoelectronic devices has given rise to the emerging area of nano-optoelectronics. In this talk I will discuss some recent results on merging plasmonics and atomically thin materials as well as the possibility of exploiting atomically thin semiconductors for integrated quantum photonics applications.</p>

We review the recent progress on the first experimental demonstration of photonic topological insulators, along with a variety of new ideas associated with it.

<p> Recently, the concept of analogue transformations has extended the potential of transformational methods. We present an overview of this approach and its application to spacetime transformation acoustics. Moreover, we show that, while inherently equipped with a complete transformational technique, the field of optics can also benefit from this method.</p>

In this paper, based on quasi-conformal transformation optics (QCTO), a synthesis design of a conformal array radiation enhanced by an all-dielectric metamaterial lens is presented. For the two-dimensional TE polarization, a physically cylindrically conformed patch array can acquire the same radiating features of a virtual planar focusing patch array, using a lens having only nonmagnetic medium parameters. Full-wave simulations are performed to justify the design approach.

In theory, a Super Phase Array (SPA) which radar cross section is greatly enhanced can be constructed. However in practice it is very difficult to make them. Here, we shall demonstrate a generic method to make the simplest possible SPA with any arbitrary geometry.

Most invisibility cloaks designed with the transformation optics approach have used purely spatial transformations. When viewed from a 4-dimensional perspective it becomes obvious that purely spatial cloak transformations introduce unwanted effects such as space-like trajectories of light. By considering time transformations in conjunctions with spatial transformations, it may be possible to mitigate these unwanted effects. This demonstrates the importance of 4-dimensional thinking for transformation optics.

We tackle the problem of investigating the near-field interaction between a dipole source and a bowtie via conformal transformation. We show how, in the electrostatic approximation, the bowtie and point dipole source is transformed into the analytically solvable configuration. The analytical solutions are validated with full-wave simulations.

<p> We report a new class of soft 3D locally resonant ultrasonic fluid metamaterials, engineered using soft-matter techniques coupled with microfluidics. Through angular-phase measurements on Gaussian pulses propagating within these acoustic metafluids, composed of “ultra-slow” porous micro-beads, the acoustic index is shown to be negative in good agreement with multiple-scattering calculations.</p>

We examine how the lasing threshold of a two dimensional photonic crystal containing a four-level gain medium is modified, as a result of the interplay between the group velocity and the modal reflectivity at the interface between the cavity and the exterior. The simulations are in good agreement with theoretical predictions.

We theoretically and experimentally demonstrate that by utilizing a new freedom introduced by spatial dispersions in the effective parameters, Brewster effect can be extended from a single angle to a range of angles, enabling wide-angle impedance matching and total transmission of light through the surface. By designing pure dielectric photonic crystals with spatial dispersions, we demonstrate an approach to achieve the omnidirectional total transparency and aberration-less virtual image. Our work reveals rich possibilities like wide-angle loss-less super-polarizer and transformation optics devices with additional phases beyond the local medium description.

We demonstrate experimentally that standing waves of polarization, as opposed to intensity, can be engaged to coherently control light-matter interactions in planar photonic nanostructures, presenting unique opportunities for all-optical data processing and polarization-dependent molecular spectroscopy.

We discuss the possibility of trapping light within the radiation continuum, based on the anomalous interaction of diffracted waves and leaky modes in diffraction gratings. These trapped optical states can be predicted within the framework of leaky-wave theory, providing physical insight on similar embedded eigenstates recently demonstrated in the literature.

We report on the electromagnetic properties of ‘focused doughnuts’ (FD), space-time localized solutions to Maxwell’s equations with toroidal topology. We show that light-matter interactions of FD pulses, include non-trivial field transformations and broadband modal excitations.

We suggest and study a three-dimensional simple-cubic metamaterial composed of interlinked tori made of a single constituent in air or vacuum. This metamaterial exhibits a sign-inversion of the Hall voltage with respect to the bulk constituent. Thus, in effect, an electron conductor appears like a hole conductor. We show that the sign of the Hall voltage can be changed by a geometrical separation parameter and that the overall behavior is robust. Simplicity and robustness bring experimental realizations of this striking sign inversion into reach.

The paper discusses the wave propagation characteristics of two-dimensional (2D) magneto-elastic lattices. Mechanical instabilities caused by magnetic interactions are exploited in combination with particle contact to induce changes in the topology and stiffness of the lattices. The propagation of in-plane waves is predicted by applying Bloch theorem to lattice unit cells with linearized interactions. Elastic wave dispersion in these lattices before and after topological changes is compared, and large differences are highlighted.

Flexible mechanical metamaterials are compliant structures with a functionality set by the geometry. In many cases, each new functionality requires a new structure, but here I show that using frustration allows one to program different functionalities in a single geometry.

We show that very good static elasto-mechanical cloaking can be obtained numerically and experimentally by direct coordinate transformation of the lattice points of a two-dimensional hexagonal lattice while readjusting the shape of the double-trapezoidal elements connecting adjacent lattice points such that their Hooke’s spring constant is fixed.

We make an origami-based mechanical metamaterial in which shape shifting is a bulk property. Our building block is the rigid 4-fold vertex, which we show is generically multistable. A simple tiling procedure instals the multistability of a base vertex into a sheet, hence creating a 2D material with many stable shapes.

We introduce and for the first time experimentally demonstrate free-standing all-dielectric metasurfaces in a variety of ultra-thin, low-loss media. Such structures provide resonant optical properties at near-infrared wavelengths and offer the possibility of extremely strong and fast optical nonlinearities underpinned by nano-opto-mechanical forces.

Phononic crystals plates are theoretically and numerically studied. They are based on two- dimensional phononic crystals of finite thickness, which are analyzed in the low-frequency limit. It is shown that for a specific type of inclusion, some resonances provide anisotropic mass density to the phononic crystal and, therefore, to the plate. Numerical calculations of the full band structure are computed for both the phononic crystal plate and the effective homogeneous plate, and a good agreement is shown.

This talk will review the development of the field of acoustic metamaterials, from the early development of key ideas, through the dramatic acceleration that paralleled the development of electromagnetic metamaterials, to what is now a distinct field with its own constraints, possibilities, and goals. To provide a common reference point, focus will partly be on similarities and contrasts with electromagnetic metamaterials: what is easier, what is more difficult, and what is simply different.

We present a theoretical investigation of the energy transfer efficiency between a pair of quantum emitters (QEs) in the presence of a graphene monolayer. At small distances between the QEs a direct interaction dominates, increasing the distance the interaction via the graphene plasmon dominates.

Targeted temperature control in nanopores is greatly important in further understanding biological molecules. Such control would extend the range of examinable molecules and facilitate advanced analysis, including the characterization of temperature-dependent molecule confor- mations. The work presented here details precise temperature control at a plasmonic nanopore. The solid-state devices are made up of a silicon nitride membrane, and gold layer patterned with a well-defined bullseye structure surrounding a nanopore. The design is optimised, through simulation and experiment, to act as nanoantenna with maximum enhancement at the centre of the pore.

A general theory for one-way optical guiding in periodic particle arrays is developed. Conditions on the asymmetry properties of the structure’s period that are necessary to obtain asymmetric dispersion are derived. The two-type rotation principle, presented and studiedin previous works on one-way guiding in particle chains, is viewed as a special design that achieves the necessary violation of the period’s symmetries. The recently suggested sector-way metasurfaces are also addressed in the present context. Examples of periodic strips and surfaces that consist of circular particles and support one way and sector-way guiding, are provided.

Surface plasmon resonators can drastically redistribute incident light over different output wave vectors and polarizations. We present Fourier polarimetry as a new experimental tool to completely characterize the angle-dependent polarization-resolved scattering of single nanostructures. To showcase the method we measured scattering and fluorescence from plasmonic bullseye antennas, which are known to beam light efficiently. We find rich structure in the angular-dependent polarization state of the scattered light, including complete conversion of input polarization from linear to circular and from one helicity to another. Furthermore, we show how Fourier polarimetry allows determining the emitter-antenna coupling in the case of antenna-mediated fluorescence.

The Hydrodynamic model can be generalized in order to describe non-local and spill-out effects near metal surfaces. Orbital-free energy functionals can be plugged-in the hydrodynamic equation in order to better describe the internal energy of an electron gas. We explore the impact of the equilibrium charge density in such model for the case of spherical nanoparticles and compare our results to density functional theory based calculations.

Chalcogenide phase-change media provide a uniquely flexible platform for both nanostructured and optically-rewritable all-dielectric metamaterials. Non-volatile, laser-induced phase transitions enable resonance switching in nanostructured chalcogenide meta-surfaces and allow for reversible direct-writing of arbitrary meta-devices in chalcogenide thin films, including dynamically re-focusable, chromatically correctable and super-oscillatory lenses, and near-infrared-resonant photonic metamaterials.

A new approach to design a metamaterial surface (meta-surface) with the objective of reducing the waveguide’s cutoff frequency of the fundamental mode is proposed. From an analytical study of the dispersion diagrams of waveguides with anisotropic walls, a hypothesis for the surface impedances is set up. By means of this new hypothesis, the design of a unit-cell is optimized. Finally, the periodically arranged meta-surface is implemented in a miniaturized waveguide and the simulation results are compared to the ones of a metallic waveguide in order to validate the approach.

<p> We demonstrate experimentally high efficiency beam shaping based on silicon Huygens-type metasurfaces. Our metasurface consist of arrays of silicon nanodisks of different sizes and are capable of converting a Gaussian into a vortex beam with 70% transmittance efficiency, independent of the polarization of the incident beam and without polarization conversion losses.</p>

We present a complete methodology for designing Huygens metasurfaces (HMS), structures combining electric and magnetic polarizable particles to tailor the fields on their aperture. This includes a spectral formalism to design HMS radiators for a given source, and a method for implementing them using printable subwavelength elements, extending their applications beyond beam manipulation.

We demonstrate the fabrication of macroscopically detectable magnetic resonances via large-scale self-assembly of gold nanorod strongly coupling with a supporting gold film. The presented cost-efficient lithography-free approach provides access to large-area bottom-up fabrication of negative index metamaterials in the optical frequency range.

In this paper, I briefly discuss the benefits of introducing recent concepts arisen from metamaterials, plasmonics and nanoantennas fields on a silicon photonics integrated platform. This could lead to the improvement of photonic integrated circuits as well as to disruptive applications in photonics.

An electrically biaxial anisotropic sample design methodology utilizing crystallographic symmetry is discussed. Sample synthesis equations based on equivalent capacitance analysis translate desired permittivity values and host materials to sample cell dimensions and are subsequently fabricated on a 3-D printer. Equivalent capacitance predictions yield permittivity tensor element values comparable to simulation results. A rectangular to square waveguide measurement system is also used to verify the sample design methodology.

“Raspberry-like” plasmonic nanoclusters constitute a first step in a bottom-up approach towards metamaterials exhibiting optical magnetism. We show that a full characterization of the electromagnetic response of plasmonic nanoclusters can be obtained by complementary techniques including polarization-resolved static light scattering, dynamic light scattering and numerical simulations. High values of the magnetic response are obtained after optimization of the morphology of the nanoclusters.

<p> In this work we report on large area two dimensional periodic metamaterial structures produced by Nanoimprint Lithography (NIL). We fabricate various metal-insulator-metal three layer systems and systematically study the effects of different symmetric patterns and different layer compositions on the optical properties in the visible range. The results of angle dependent transmission and reflection measurements reveal that our structures are very promising candidates for optical metamaterial.</p>

We study RF response of the individual meta-atoms in the superconducting metasurface built with two dimensional array of RF Superconducting Quantum Interferometer Devices (SQUIDs). We tested a metasurface sample with 21X21 RF SQUID array in a waveguide test chamber designed in a way to achieve a uniform microwave RF signal excitation over the entire array. The demonstrated tunability of 2D SQUID metasurface resonance frequency with extern magnetic field is 56% (8 - 12.5 GHz). Moreover, RF currents distribution in the SQUIDs array is observed with Laser Scanning Microscope.

A photonic analogue of the electrical conductivity is put forward. In the same manner as in electronics the conductivity characterizes the electron flow for an electromagnetic excitation, the photonic conductivity describes the induced light flow in a material subject to mechanical oscillations.

<p> A usually accepted approach of combination of Maxwell equation with density matrix formalism leads to a paradox for the radiative loss description. This roots into the basic principles from which Maxwell equations are elaborated.</p>

We demonstrate the first addressable reconfigurable photonic metamaterials thus enabling control over optical material properties with simultaneous spatial and temporal resolution. Potential applications of random access metadevices include active focusing, beam steering, dynamic transformation optics and video holography.

We have studied the effect of a high photonic density of states provided by a metamaterial environment on the dynamics of nanodiamond based nitrogen-vacancy (NV) centers. We have experimentally demonstrated the broadband enhancement of single-photon emission from nanodiamond NV centers coupled to a planar multilayer metamaterial with hyperbolic dispersion. In addition, we have studied the influence of Purcell effect on the fluorescent contrast between the NV center spin states.

<p> An investigation on gap solitons localized within one-dimensional Kerr/metamaterial heterostructures in periodic, quasi-periodic and disordered arrangements is carried out. Transmission is obtained by considering losses within the metamaterial layers. Under suitable conditions, multistability, transmission switching and soliton formation are observed for all arrangements.</p>

We present a plasmonic coupled resonator optical waveguide (CROW) that utilises the broad resonances and subwavelength nature of localised surface plasmons to produce a compact CROW design where the plasmonic nanoparticles are side coupled via a diectric waveguide. Such a scheme features a highly tunable low-loss central band where coupling to the plasmonic nanoparticles is systematically avoided close to the band edge. Furthermore, such low loss modes are preserved in the form of Fabry-Perot type resonances in finite sized CROWs; leading to cavity modes with quality factors of many thousands and whose upper limit depends only on the CROW length. By varying the geometric parameters the losses into dissipative and radiative channels can be reduced and it is also possible to efficiently outcouple the energy into the waveguide. This ability to minimise the plasmonic losses whilst maintaing the dispersion charateristics of the structure could make plasmonic CROWs an effective cavity desing for on-chip laser devices and other applications.

We derive a closed-form expression that accurately predicts the peak frequency-shift and broadening induced by tiny perturbations of plasmonic nanoresonators without critically relying on repeated electrodynamic simulations of the spectral response of nanoresonator for various locations, sizes or shapes of the perturbing objects. Accurate predictions are obtained for a broad panel of nanoparticle shapes and sizes, used in various plasmonic nanosensors. The expression gives quantitative insight, and combined with an open-source code, provides accurate and fast predictions that are ideally suited for preliminary designs or for interpretation of experimental data. It is also valid for photonic resonators with large mode volumes.

<p> Quasi-Periodic (QP) particle chains exhibit unique properties not observed in periodic ones. Furthermore, they inherently support significant long-range interactions and radiation to the surrounding medium. Hence they are fundamentally different from traditional QP structures governed by the Harper’s model or the almost-Mathieu operator. We present a mathematical framework for QP particle chains and study their electrodynamics. They support guided modes that exhibit a complex interaction with the light cone, and possess a twodimensional fractal-like structure in the frequencywavenumber space thus making the unique definition of modal phase velocity impossible. However, a well-defined group velocity is revealed due to the fractals inner structure. We also show initial study of non-reciprocal QP structures.</p>

We present our recent advances in nanoscale lasing action enabled by plasmonic resonances. First, we study lasing action in plasmonic crystals incorporating optically pumped four-level gain media. We show that the excitation of dark plasmonic resonances (via the gain medium) enables accessing the optimal lasing characteristics of this class of systems. Second, we analyze the conditions for the emergence of self-sustained laser oscillations in an optically-pumped long-range surface-plasmon structure that includes plasmonic Bragg mirrors as optical feedback mechanism.

We propose a method for efficiently stacking complex homogeneous metasurfaces (MS) to create integrated optical devices. A theoretical framework for fast numerical calculations is given by means of a scattering matrix algorithm. As an example we use a combination of periodic metallic layers and dielectric spacers to design a frequency selective mirror.

<p> We present a novel high-index dielectric nanoantenna with a tunable magneto-electric coupling. The key to achieve such bianisotropic (magneto-electric) coupling is breaking the symmetry of a nanoantenna. This coupling provides interesting optical features for an individual nanoantenna as well as for planar arrays made from such nanoanetnnas.</p>

Here, we will experimentally demonstrate a dielectric metasurface based on silicon nanodisks, with close to unity transmission over a broad spectral range in the visible. Full 2π phase control is shown by beam deflection with 75% efficiency. In additiona, it is theoretically predicted and experimentally verified that a properly designed all-dielectric metasurface can exhibit Brewster’s effect potentially for any angle, wavelength and polarization of choice.

<p> We report the realization of highly efficient geometric phase metasurfaces. A 16-level phase CGH design is realized using the metasurface, exhibiting high quality holographic images with very high fidelity and a broad bandwidth from visible to near infrared. The overall efficiency reaches 80%, greatly surpassing previously demonstrated metasurface based CGH. The GEMS based CGHs with their accurate phase modulation, high efficiency, and simple fabrication procedure compared to conventional multi-step phase holograms, are highly promising for various practical applications ranging from laser holographic projection to data storage and beam shaping.</p>

Microstrip lines loaded with pairs of electrically coupled complementary split ring resonators has been studied including the effect of coupling between two CSRRs. It could be applied to the design of stop band filters and differential sensors.

<p> In this paper metamaterials based on resonators longer than the unit cell is introduced. The resonator is just a simple conducting strip bent several times. A broadband left-handed metamaterial has been designed with a 37% relative bandwidth. Besides, there is not a fundamental limitation for the smallness of the unit cell.</p>

We propose a method to suppress the scattering based on an ultrathin metasurface in a broad frequency band. The designed metasurface is composed of two kinds of units with different geometries and reflection phases, which provide destructive interference in most of reflected directions, suppressing the main lobe and side lobes significantly of the scattering pattern. Full-wave numerical simulation results show that a large bandwidth of 1.74 GHz is achieved using the proposed metasurface with the thickness 1 mm, which suppresses the scattering by at least 10 dB.

In this contribution we discuss the design of a Frequency Selective Surface (FSS) serving as planar, dual-band, low-frequency Artificial Magnetic Conductor(AMC). The unit cell geometry of the AMC is based on meander structures to reduce its size and allow for the design of two separately tuneable resonances. The FSS is constructed from two single-sided Printed Circuit Boards (PCBs) manufactured from cost-effective FR-4 separated by nylon spacers. The unit cells contain lumped elements for tuning of the individual resonances and immunity to permittivity variations of the substrate. The numerical simulation results are discussed and compared to measurements obtained from manufactured specimens.

We propose the concept of coding metamaterial, which is composed of “0” and “1”elements for 1-bit coding, and “00”, “01”, “10”, and “11” elements for 2-bit coding, etc. Different from the conventional metamaterial that utilizes effective medium parameters to control the electromagnetic (EM) waves, the coding metamaterial makes use of different sequences of spatial codes to manipulate the EM waves. We present a unique metamaterial particle to create “0” or “1” response controlled by a biased diode. Based on this particle, we propose the concept of digital metamaterial whose unit cells possess either “0” or “1” state. Using a field-programmable gate array (FPGA), the coding sequences on the digital metamaterial can be written in program and controlled in real time. Hence a single digital metamaterial has the ability to manipulate EM waves in different manners by pre-designed program, realizing the programmable metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments in microwave and terahertz frequencies.

Here we study the electromagnetic instabilities in a system formed by two twin semiconductor waveguides separated by a vacuum layer in two different scenarios: (i) semiconductor slabs in relative motion, and (ii) in the presence of an electron drift. It is shown that the flow of electrons can mimic the response of a moving material slab, inducing exponentially growing light oscillations. The oscillations result from the hybridization of the surface plasmon polaritons (SPPs) supported by each air-semiconductor interface.

We show that plane waves can fully “tunnel” through a thin metallic layer perforated with a two-dimensional subwavelength array of tiny holes. It is shown that a parity-time-symmetric pair of a lossy layer in front and an active layer behind the metallic layer makes both forward and backward scattered powers zero.

We show that PT-symmetry concepts, combined with an effective nonlocal response, allow realizing all-angle negative refraction and aberration-free optical imaging. The designed PT-symmetric lens is an example of “absolute optical instrument”, with similar imaging properties as DNG lenses, but without some of their drawbacks.

This paper analyses the eigenfrequencies of an infinitely long chain of microresonators with PT symmetry. The results show that the depth of modulation of the real part of the refractive index can be used to control the threshold point of the PT structure.

Exploration of the interplay between material gain and loss can lead to novel metamaterials of unique performances. Here we demonstrated a single-mode microring laser based on parity-time symmetry breaking.

Phononic crystals (PCs) commonly consisted of two materials with huge contrasted elastic properties and mass densities. In this paper, the propagation of Lamb waves in the composted PCs is investigated. Coupling effects of band gaps for low order Lamb wave modes are found. Crucial parameters such as the periodical arrangement of the scatterers are discussed in detail for the influence of band structures.

Double Fano resonances are observed in a planar composite metamaterial possessing tripod plasmonic resonances, where a common subradiant driven oscillator is coupled with two superradiant oscillators. As a classical analogue of four-level tripod atomic system, the extinction spectrum of the composite metamaterial exhibits a coherent effect based on double Fano resonances. It is shown that a transfer of the absorbed power between two orthogonal superradiant oscillators is mediated by a common subradiant oscillator.

Simulation has been conducted of the optical properties of gold nanopillar array with each pillar consisted of two gold layers. It is shown that in near-infrared range (optical communication frequencies) such fish-net structures possess negative refraction index and optical magnetism. Due to possible fabrication of such fish-net metamaterial using bottom-up approach on cm-scale there are wide perspectives for their application for creation of various devices of nanophotonics.

The construction is proposed of the hyperbolic metamaterial for an optical spectral range with the expanded working range of wavelength due to periodic system of nanorods in a definite range of diameters and heights. The construction is fulfilled on aluminum-oxide ceramics with the periodic system of nanoholes with the diameters from 30 up to 50 nm filled with particles of noble metal, which forms metal nanorods with the height from 3 up to 10 diameters of nanorods from the side of the surface of dielectric substrate turned toward the source of electromagnetic radiation. To provide mechanical strength the thickness of the dielectric substrate is to be not less than 30 μm.

<p> We propose a new design for imaging via isotropic refractive index of heterogeneous medium. By aid of conformal map, one transfers the full Maxwell fisheye into a mapped profile within a unit circle. By this trick, the imaging resolution of this new profile is maintained as good as the truncated Maxwell fisheye profile or its conformally-mapped counterpart in previous literature.</p>

We demonstrate oscillation between the excited states of an atom embedded in a photonic crystal using the external coherent control laser, which may act as a qubit operation for quantum information processing.

We propose an intracavity plasmon absorption spectroscopy method based on graphene active plasmonics. Maximum sensitivity is reached in the vicinity of the plasmon generation threshold. The giant amplification of sensitivity in the graphene plasmon generator is associated with a huge path length, limited only by the decoherence processes.

We present a class of aperiodic elastic structures which exhibit 3D-folding motion with arbitrary complex deformations. We use this large design space to encode smart functionalities such as surface patterning, mechanical reponse and multistability.

We investigate the spontaneous emission (SE) near graphene grown on SiC in the presence of an external magnetic field. The magnetic field can induce a variation of 99 % in the SE, suggesting that it may be applied to tune and tailor light-matter interactions in graphene plasmonics.

<p> Electric response of the objects covered by spherical and cylindrical shells with radially anisotropic permittivity is studied in quasi-static approach. We show that shells with radially inhomogeneous permittivity components can provide the ideal cloaking. We established conditions necessary for reaching the ideal invisibility of the cloaked structures.</p>

<p> We demonstrate a novel method to measure chromatic aberrations of microscope objectives with metallic nano-particles using incoherent white light. We show a direct correlation between the focal wavelength and the longitudinal chromatic focal shift through analysis of the scanned extinction spectra of a single nano-particle through a lens’s focal plane.</p>

We study the hybridization of two graphene based one dimensional edge surface plasmon polaritons (1DSPP). We discuss normal and anomalous coupling between 1DSPP and we exploit the sensitivity of these devices to the carrier concentration on graphene sheets to propose metamaterials dynamically tunable by means of an electrical gate.

Spontaneous parametric down-conversion in a metal-dielectric interface in the case of oblique laser excitation is considered. In this case it is possible to generate pairs of surface plasmon polaritons with high efficiency, if the angle of excitation corresponds to the Kretschmann configuration for generated plasmons. The efficiency can be additionally increased/enhanced if to use metal-dielectric interfaces with long-range surface plasmon polaritons and/or a properly nanostructured metallic film, allowing one to directly excite surface plasmon polaritons and to fulfill their phase matching condition with generated surface plasmon polaritons.

In this study we suggest to control the reflectance and transmittance of monolayer graphene placed between silicon relief grating and liquid crystal slab by reorienting the liquid crystal director. Our modelling of the electric control of graphene plasmon in the hybrid system under investigation involves the following elements: liquid crystal director spatial profile, electric field distribution in liquid crystal and electromagnetic wave propagation through the sandwich: liquid crystal-monolayer graphene-silicon grating.Put your abstract here

We report here on the possibility of realization negative permeability in 3D metamaterial made of planar spiral superconducting resonators. A theoretical study of the electrodynamic response of a 3D array of monofilar Archimedean spiral resonators to an externally applied alternating magnetic field is presented. Such metamaterial with the dissipation parameter taken from typical experimental data shows a few of narrow frequency bands in which the real part of the permeability is negative.

In this paper, we investigate the conceptual realization of a concentric bi-layer composite made of the same isotropic and homogeneous semiconductor material with various porosities and show the possibility of simultaneous cloaking performance for both heat flux and electric current without disturbing external fields.Put your abstract here

<p> The effect of annealing on the optical and morphological properties of Au metal island and continuous films was studied by spectroscopic ellipsometry and SEM. It was found that annealing promotes reshaping and formation of bigger islands and breaks the continuity of 18 nm Au coating at temperatures higher than 200oC.</p>

By illuminating a single rectangular hole drilled in an opaque metal film with parallel electric and magnetic fields, it is found that the magnetic field dominates the response of the aperture. This study could be useful for the design of new magnetometry strategies.

We present a method for calculating the plasmonic and photonic enhancement of the absorption in solar cells. The method involves coupling between a transfer matrix method to describe light propagation in the layered stack and Mie theory for calculating the absorption and angular scattered field distribution from the nanoparticles. We also compare the method to rigorous simulations.

<p> Put your abstract hereWe present the numerical design and experimental validation of a dielectric photonic crystal structure that provides tunable directional emission and frequency splitting operation. The configuration consist of a line-defect photonic crystal waveguide that transmits energy to a properly designed surface and grating bilayer. The operation of the device is based on the excitation of highly localized surface waves and their selective coupling to outgoing propagating waves. The device is characterized by low beam cross-talk and reduced return losses.</p>

In addition to electric responses, it is of particular interest to produce artificial optical magnetism in the visible regime. To this end, metallic nanoparticles can be arranged to have unique tailored optical properties at visible frequencies. DNA-origami is a bottom-up approach which can successfully template plasmonic materials at the nanometer scale, in large quantities and high yields. Herein we applied this method to fabricate self-assembled ring-shaped plasmonic metamolecules that are composed of four to eight precisely organized metal nanoparticles. Scattering spectra shows that our DNA templated plasmonic structures support unique electric and magnetic plasmon resonance modes, in good agreement with numerical simulations. We stress the possibility to create bulk plasmonic materials and metamolecules that may be applied as building blocks in plasmonic devices.

Ordered composite materials containing silver nanoparticles on the surface of polymer matrix were formed on the basis of honeycomb carboxylated nitrocellulose film. The optimal conditions which allow forming silver layer only onto the surface of polymer honeycomb films were determined. The relationship between morphology of proposed films and their optical properties was established. The effective medium theory is elaborated for these films. It is established that proposed structures can display the properties of metamaterial in near IR spectral region.

<p> Composite Langmuir-Blodgett (LB) mono- and multilayers of polystyrene-poly-2-vinylpyridine with silver nanoparticles of size 5 to 91 nm were formed on silicon and glass surfaces. Its morphology and optical properties (phase shift) were studied.</p>

It is shown that at focusing with flat lens of the field created by the slit with the size larger than the wavelength, the intensity distribution has two maxima and the focal distance increases. The proposed scheme combines flat lensing and generation of incomplete Airy beams.

<p> We report on the role of the coupling of the modes of Mie resonances in an all- dielectric metamaterial so as to achieve negative index at terahertz frequencies. We studied this role according to the lattice spacing and according to the frequency overlapping of the modes of resonance. We show that negative effective index requires sufficiently high mode coupling.</p>

For the first time, we present feasible and effective approach to direct optical probing of transverse electric (TE) plasmons in graphene, experimentally demonstrating significant plasmonic coupling to an incident wave in electrically doped multilayer graphene sheet.

An asymmetric bull's eye metasurface has been investigated, which exhibits remarkable unidirectional acoustic transmission behavior. With changing the periodicity, the transmitted acoustic energy flux keeps unchanged while the frequency of the transmitted waves can be modified. The metasurface may have potential application in ultrasound diagnosis and therapy.

Measurements of the negative optical phase shifts of Ag/TiO2 and Ag/SiO2 bilayer films have been carried out with the modified walk-off interferometer. Appearance and monotonic rise of the phase shift anisotropy for p- and s-polarization by increasing incidence angle has been revealed experimentally. The results of measurements have shown rather good coincidence with theoretical calculations.

The technique of improvement of the Maxwell-Garnett theory of electric permittivity averaging for precise evaluation of composite material dispersion is demonstrated. According to this approach, a set of adjustable coefficients in depolarization factor are introduced, which are determined in the process of fitting simulated optical spectra to experimentally measured ones. The presentation gives the results of depolarization coefficient calculation from reflection and transmission spectra of simulated in finite difference time domain method test structures and from experimentally measured spectra of samples with non-uniform nanoparticles distribution. The proposed approach shows good convergence with the experimental data and could be used as a versatile dispersion model in optical metrology of composite materials with unknown arbitrary concentration and shapes of inclusions.

We experimentally demonstrate Fano resonance in a metamaterial composed of an asymmetric ferroelectric wire pair. By assembling two parallel ceramic wires of different lengths, sharp Fano-type transmission spectra emerge as a result of interference between the quadrupole and dipole modes. A rapid increase in group delay is observed as a result of a steep variation in transmission phase. The location of the Fano resonance peak depends on the wire separation and degree of asymmetry. Furthermore, Fano resonance can be thermally modulated from 9.8 GHz to 10.5 GHz as the ambient temperature varies from 10°C to 50°C, as a consequence of the temperature dependence of the permittivity of the ceramic material.

we present experimental demonstration of a flexible and mechanically tunable metamaterial absorber composed of dielectric resonator stacked on a thin conductive rubber layer. A near unity absorption is observed due to strong local field confinement around magnetic Mie resonance of dielectric resonator. Furthermore, the interspacing between unit cells is modulated dynamically under uniaxial stress. Owing to the decreases of longitudinal coupling between neighboring unit cells, the resonant absorption peak is reversibly tuned by 410 MHz as the stain varies up to 180 % along H field direction. On the contrary, the resonant absorption state is nearly independent on strain variation when external stress is applied along E field direction, due to the weak transverse interplaying. The mechanically tunable metamaterial absorber featured by flexibility paves a way forwards for actual application.

The electric field enhancement properties of the active gold nanoshell have been investigated. An extremely high SERS G factor on 1019-1020 can be obtained in the optimized active gold nanoshell. The optimized active gold nanoshell has a high efficiency of SERS effect.

Here, we introduce a new labyrinthine type unit-cell for phase engineering of the transmitted wave front. Despite the complexity of the shape, the structure is very easy to design. Moreover, it is based on well defined mathematical formula which facilitates the design and optimization procedure.

We theoretically study the properties of the longitudinal magnetophotonic intensity effect in plasmonic structures with the magnetic dielectric possessing absorption. The effect is the magnetization-induced resonant change in transmittance. It is shown that there exists an optimal value of the absorption coefficient at which the effect reaches its maximum.

<p> We consider graded plasmonic antennas comprising linear arrays of metal nanoparticles of different sizes and varying inter-particle spacings. We demonstrate that the position of electromagnetic field and temperature hotspots in the vicinity of such systems can be controlled by angles of incidence or the wavelength of the excitation.</p>

Graphene, as a sheet conductor, supports surface plasmon modes, which, due to the zero band gap of its electronic stucture, can be absorbed and re-emitted by the creation or anihilation of electron/hole pairs. This opens up the question, whether plasmons with gain can be supported by partially inverting the carrier system. We show that, by calculating the exact complex-frequency plasmon dispersion (\textsc{cfpd}) of such inverted systems, plasmons can be amplified by stimulated emission even in cases of finite scattering rates, finite temperatures, and extrinsic chemical doping. From here, given these non-equilibrium carrier distributions, we investigate the rates of electron-hole recombination via plasmonic channels and find they are a factor of 5 faster than previously predicted.
Media link(s):

See our recent publication in PRB,

http://dx.doi.org/10.1103/PhysRevB.91.075404

Using our proprietary in-house Fourier modal method technique, we investigate selected periodic arrays of nanostructures inspired by metasurfaces and evaluate their potential for surface plasmon resonance (SPR) effect used in sensor applications. We evaluate spectral sensitivities of SPR and relevant figures of merit, enabling direct comparison of various structural morphologies.

This paper reports design of a very low-cost (less than 2000 USD) CVD reactor for graphene synthesis, based on readily available off-the-shelf components. The reactor is intended for in-house graphene synthesis in metamaterial research. The reactor was manufactured and tested, and synthesized graphene samples were found to be of a high quality

Angular reflection spectra of 1D arrays of grooves in a metal film in the Kretschmann configuration has been studied numerically. The case of a wave incident in the plane parallel to the grooves has been considered. For the s-polarized incident wave two types of features in the reflection spectra occur: the first is associated with excitation of channel plasmons in every single groove of the array and the second is the Wood anomaly-like feature.

Photon-phonon interaction is considered in a one-dimensional disordered metal photonic crystal, which is metal plates of different thickness arranged in parallel with equi-intervals. Each metal plate is assumed to be artificially driven, and lattice vibration is introduced to the photonic crystal. A simple model is numerically analyzed, and the following novel phenomena are found out. The lattice vibration generates the light of frequency which added the integral multiple of the vibration frequency to that of the incident wave. The incident wave with frequencies near the plasma frequency is resonantly amplified. Resonant peaks change with the frequency and the phase of lattice vibration.

Transformation optics theory led to study the possibility of controlling heat flow. Using concepts of anisotropy and metamaterials, it is possible to design devices for heat cloaking, concentration and rectification effects at the macro-scale. Computational and experimental validations were performed. Both results have shown the desired behavior so far.
Media link(s):

For a graphical abstract follow this link.

Terahertz metamaterials typically have non-ideal parallel plate capacitive gaps due to microfabrication limitations. This work examines the exact solution to the square parallel plate capacitor and finds a valid approximation for capacitance in non-ideal geometries, when the gap size is comparable or larger than the dimensions of the plates.

This work is devoted to the numerical calculation of the effective constitutive parameters of the carpet cloaking device and to the numerical simulation of this cloak in COMSOL Multiphysics software for the terahertz frequency range. Two different types of low boundary depends of curvature was considered.

We introduce a novel scheme to generate Plasmon Induced Transparency (PIT) by hybridizing two concentric-twisted double split ring resonators (DSRR). We demonstrate that counter-directional twisting of small SRRs can perturb both SRRs response eventuating new states through red shift of the first and blue shift of the second resonance. Contrarily, by co-directional twisting of small SRRs and focusing on first resonance, we manifest PIT which is formed as a result of splitting the first resonance into two dependent bright modes.

The feasibility of a D-dot wire/D-dot loop experiment in the optical regime is studied. Currently available materials, measurement techniques and fabrication methods, needed for the production of a sample with D-dot-based structure, are compared and discussed.

It is well known that the emission/optical properties of quantum emitters such as quantum dots are influenced by their local electromagnetic environment. We have fabricated structures comprised of silver optical antennas in close proximity to lithographically patterned aggregates of quantum dots. We report on the emission spectra and lifetime of the coupled system as a function of antenna size and antenna-aggregate separation distance

Distribution of electric fields normal to the antenna plane in the depth direction was experimentally investigated by using mid-infrared circular antennas formed on atomic-layer-deposited Al2O3/SiO2/Si and SiO2/Al2O3/Si. The field distribution was estimated by observing the surface phonon polariton signals originating from the SiO2 layer.

Gradient all – dielectric nanostructures, based on the controllable nonlocal dispersion and providing broadband antireflection tunneling regime of energy transport in visible and infrared spectral ranges, almost independent upon the nanostructure’s total thickness, are designed and tested.

In this work, disks of silica aerogel are examined theoretically and experimentally as building elements of an acoustic metamaterial. The demonstrated results show that the flexural motion of the disks can act as a negative effective mass over a broad frequency range below the modal plate resonance.

<p> The transmission/reflection spectra of electromagnetic waves through a 1D system containing alternate layers of air and a uniaxial anisotropic left-handed material are investigated. For oblique incidence, even in the presence of loss/absorption, longitudinal bulk-plasmon polariton modes are found in the neighborhood of the plasmon frequency along the optical axis.</p>

<p> A method of the separation of air and sound in acoustic waves is suggested. It is composed of an array of the resonators and each resonator has a macroscopic subwavelength hole in the center. The principle is based on two wave theories of diffraction and acoustic metamaterials. When the wavelength of the incoming wave is much larger than the size of the holes, it will be diffracted strongly into the holes. The negative effective bulk modulus of the resonator produces evanescent wave with the air holes of subwavelength diameter existed on the surfaces of the plate for macroscopic air ventilation. A model of soundproof plate which is transparent to airflow is designed. The numerical simulation of the soundproof ability with air flow was presented.</p>

We studied two optical modes of the gyrotropic slot waveguide consisted of a magnetic dielectric sandwiched between to different metal walls. Different types of modes are identified including backward anti-symmetric plasmonic mode that has opposite direction of the phase and group velocities. Effect of the magneto-optical nonreciprocity in a transversal magnetic field is revealed and its pecularities for the backward mode are studied.

<p> The excellent photoluminescent properties of Graphene quantum dots (GQDs) makes them suitable candidates for biomedical applications, but their corrosion resistance, passivation behaviour and cytotoxicity have not been extensively studied. Here we report a detailed and systematic study of the passivity of GQDs. The GQDs sample was prepared from multi walled carbon nanotubes (MWCNTs) with green light (455nm) and fully characterized by means of atomic force microscopy (AFM), Fourier transform infrared spectrophotometry (FTIR), Raman spectroscopy, and photoluminescence (PL) and photoluminescence excitation (PLE) analysis. The formation and stability of the passive layer was studied by open circuit potential, cyclic voltammetry (CV) and tafel plots. The electrochemical results also simulated equivalent corrosion measurements suggested by passive layers. In the measured photoluminescence (PL) spectra, the emission peak is shown to be at ∼455 nm, also confirmed by PLE spectra. In addition, the good optical properties of the GQDs are attributed to the self-passivated layer on the surface of the GQDs as revealed by electrochemical tests. The data explores a new generation of coating technology for GQDs that can also profoundly impact biological and biomedical research.</p>

We present a sub-wavelength imaging of the modes localized in silicon microring resonators, obtained by combining near-field scanning optical microscopy with resonant scattering spectroscopy. The different spatial distribution of the TE and TM modes allows us to clearly identify the two mode families.

<p> We demonstrate experimentally for the first time eigen modes in silicon nanotoroidal structures in visible wavelengths. The structures have been designed and created using recently developed laser printing technology followed by FIB or HIM processing.</p>

Morphing turns out to be a fast and accurate tool for wave pictures associated with an ellipti-cal invisibility cloak of certain eccentricity deduced from the exact computation (e.g. using a finite element method) of a circular and an elliptical cloak of larger eccentricity, thereafter called the source and desti-nation images. We shall ask ourselves why this is the case and whether this holds for more general trans-formation optics based media.

Abstract We have adapted the concept of transformational thermodynamics, whereby the flux of temperature is controlled via anisotropic heterogeneous diffusivity, for the diffusion and transport of mass concentration. The n-dimensional, time-dependent, anisotropic heterogeneous Fick's equation is considered, which is a parabolic partial differential equation also applicable to heat diffusion, when convection occurs, for example, in fluids. We initially used finite-element computations to model liposome particles surrounded by a cylindrical multi-layered cloak in a water-based environment, and for a spherical multi-layered cloak consisting of layers of fluid with an isotropic homogeneous diffusivity, deduced from an effective medium approach [1]. Independent research groups have applied our model to applications implicating the protection of steel by protecting concrete against chloride ions penetration [2] as well as for the design of water-based invisibility cloaks [3]. We now investigate the utility of the biocloak for vectorization of drugs [4].

Metamaterial photonic crystals composed of dispersive left-handed and right-handed materials were investigated numerically. In two-dimensional system, the distinct stop band was observed when the dispersive metamaterials are embedded in a positive-refractive-index medium. A novel numerical technique for the finite-difference frequency-domain method, which is applicable to dispersive (meta)materials, is also proposed.

Beam polarimetry is a versatile tool in optical technology enabling the measurement of the light polarization state. In this work, we demonstrate an on-chip polarization analyzer working at telecom wavelengths that allows for a direct measurement of the Stokes parameters of an incoming plane wave. The analyzer consists of three silicon nanoantennas coupled to three waveguides (having six outputs) so that each nanoantenna responds to a certain polarization state by changing the amount of optical power coupled to each waveguide as well as the direction of propagation along the coupled waveguide.

The ultrastrong interaction of matter with the LC-mode of SRRs is demonstrated in the THz frequency range. By scaling the SRR dimensions, the anti-crossing between the SRRs and the cyclotron transition of a two dimensional electron gas is observed. For small structures, where the wavelength of the SRR-resonance has a sub-linear dependence on SRR-dimensions, we start to observe a geometry-induced reduction of the light-matter interaction strength.

A resonator made of a planar high-permittivity dielectric ring coated with graphene is considered. It is shown that the resonant magnetic response of the ring to an axially applied time-harmonic magnetic field can be efficiently tuned by electrical gating of graphene.

It is shown that in in-plane magnetized ferromagnetic films there exist backward volume waves with a negative group velocity anti-parallel to the in-plane wave vector of propagation. Analytical expressions of the group velocity are given. Analogies and differences with electromagnetic waves propagating in backward-wave isotropic materials are discussed.

We explore possible applications of our previously-introduced nonlocal-transformation-optics framework to scenarios of interest for dispersion engineering. In particular, we address the design of nonreciprocal effects (such as unidirectional propagation), as well as exotic effects such as the "frozen-mode" regime and Dirac-cone-type dispersion.

We investigate how the phonon response in a system of two single crystals can be used for far field imaging of subwavelength features. By cutting the crystals into suitably designed prisms, an expanded image can be obtained and projected into the far field. We show simulations using triglycine sulfate.

<p> We give a comparative analysis of different realization of surface plasmon amplification: lumped spaser, in which the field is localized at bounded subwavelength inclusion and spasers driven by an external field. It is shown that transition from lumped spasers to driven ones makes easy the achievement of conditions when coherent near fields prevail over incoherent ones.</p>

The simplest possible fold pattern that allows for rigid folding motion, the 4-vertex, is a one degree-of-freedom mechanism with two distinct branches of motion. When we tile 4-vertices into a sheet, a structure emerges that has exponentially many 1 D.o.F. branches.

<p> This paper deals with numerical research of magneto-optical effects inside magnetoplasmonic crystals (MPC). Numerical simulation allows to investigate both the propagation of surface plasmon modes and the generation of waveguide modes. Influence of external magnetic fields on electromagnetic wave propagation inside MPC also is considered. We introduce new open source finite-difference time-domain (FDTD) code for numerical simulation with the assistance of up-to-date GPU architectures and CUDA technology. Due to high performance algorithms named DiamondTile it is possible to deal with fast simulation and interactive regime. The benchmark performance of our code is offered. Numerical simulation are verified and compared with experimental and theoretical results. Angular-frequency transmitance spectra of the MPC is obtained and discussed.</p>

In this paper we have presented some recent advances regarding the reduction of major earthquake effects on urban infrastructures, applying invisibility methods assisted by innovative technologies, respectively anti-seismic shield and seismic dampers.

The condition to obtain perfect broadband absorption in systems made of lossy resonant elements coupled to a rigid backing waveguide is theoretically and experimentally discussed in this work. We obtain a procedure to engineer the losses of the system to find the condition of perfect absorption using the information provided by the zeros of the reflection coefficient in the complex frequency plane. The results shown here can have applications in several branches of physics as optics, microwaves and acoustics.

Close to the magnon resonance frequency, antiferromagnets act as indefinite permeability media, i.e., not all their permeability tensor components are of the same sign. This behavior can induce a series of optical effects such as all-angle negative refraction. In the presence of an external field, a non-reciprocal lateral shift on reflection is also possible. We illustrate these effects using the example of MnF$_2$. In this crystal both the angle of refraction and the Goos-H\"anchen shift become tunable when an external magnetic field is applied.
Media link(s):

This work is based on:

Tunable all-angle negative refraction using antiferromagnets

and

Spin canting induced nonreciprocal Goos-Hänchen shifts

Put your abstract We calculate the temperature dependent electromagnetic responses of a relativistic gas of free electrons using quantum field theory methods. Polarization and magnetization are related to the polarization tensor of finite temperature QED. They depend on both the electric and magnetic fields. We compute the refraction index from the wave equations in the medium. In the non-relativistic limit, expressions reduce to well-known results. Our generalized expressions depend on two independent functions, and should be relevant in astrophysical and synchrotron environments.

We analyse several thermal devices such as invisibility cloaks or concentrators designed via different geometric transforms. We define a quantitative criterion in the frequency regime for the effectiveness of these thermal devices through the calculation of the standard deviation of the isotherms and of the heat flux distribution. We also study the effectiveness of engineered multilayered thermal devices defined through homogenization process using concentric or orthoradial layers. Thus, we determine the number of layers required to approach ideal thermal devices effectiveness.

Refractive index sensors based on localized surface plasmon resonance rely on tracking the extinction properties changes when the dielectric environment of nanoparticles is modified. It is shown that improved sensing characteristics can be obtained if reflectance measurements of a nanoparticle system located close to a metal surface are used.

We demonstrate numerical simulations of recently reported waveform-selective metasurfaces by developing a new electromagnetic (EM) simulation method based on the transmission line modelling (TLM) method. As opposed to a conventional method integrating an EM simulator with a circuit simulator, this simulation method allows us to fully visualise electromagnetic fields around the metasurfaces. Therefore, this demonstrates how the waveform selectivity varies the surrounding fields in response to the pulse width of the incoming wave even at the same frequency. This simulation method is expected to be useful for testing other kinds of circuit-based metasurfaces and metamaterials as well.

We examine the excitation of resonant modes inside eccentrically layered cylindrical active nano-particles. The nano-particle is a three-layer structure comprised of a silica core, a free-space middle layer, and an outer shell of silver. It is shown that a concentric configuration, initially designed to excite e.g., a strong dipole mode, induces, at the cost of this mode, a progressively stronger asymmetric quadrupole mode with the increasing eccentricity of the nano-particle. The direction of the main beam of this quadrupole mode, which can be further optimized by proper adjustments of the gain constant, is shown to be controlled by the direction of the core displacement. The present eccentric active nano-particles may provide alternative strategies for directive near-field radiation relative to the existing designs.

<p> In this contribution, we present our latest results concerning the design of microwave mantle cloaking devices and show some of their applications in different operative scenarios. We start by describing the analytical models of the anisotropic metasurfaces needed to achieve a scattering cross section (SCS) reduction for any polarization of the incident field and, then, we prove the effectiveness of these formulas in a representative antenna scenario. Finally, we show that the proposed formulas still hold in the case of multilayered cloaks that, being able to tailor different scattering modes excited by an object, can be successfully used to cloak non-electrically small objects and/or achieve a wideband cloaking effect of 2D objects.</p>

The left-handed properties of layered chiral structure based on rosette massive has been demonstrated by the numerical simulation and experimentally for the waves with a one of circular polarization in the millimeter waveband. Our simulation model helps to explain the unusual dependence of the frequency of area with the highest values of the polarization plane rotation angle on the structure pitch.
Media link(s):

Gif-animation of simulation of propagation RCP-wave through the layered chiral structure at f = 37.25 GHz:
http://i66.fastpic.ru/big/2015/0320/31/fef248d2bdc9d9d24d0580647974fc31.gif

The present study considers half-periodic segment of the DNA-type helix as bianisotropic particle. It has been established that the half-periodic segment of helix has the same distribution of current as long DNA-type helix. The geometric parameters of perfect conductive helix are taken from measured results of real DNA helix. The numerical simulations are used to calculate an individual polarizabilities of DNA-type helix in soft X-ray range. As a result, such bianisotropic particle has equally relevant dielectric and magnetic moments at resonance wavelength. The obtained properties open opportunities for creating low reflectivity polarizers, perfect absorbers, antireflection coatings, and metamaterials with negative refractive index based on DNA-type helices.

Design of ultrathin single-layer plasmonic absorber for infrared spectral range is proposed and characterized using numerical simulations. Nearly perfect absorption is predicted for optimized structure geometry, with the possibility to obtain both narrow and broadband response by tuning the structure geometry and parameters of the initial material, assumed to have optical properties of a heavily-doped semiconductor. The absorber exhibits consistent polarization-independent performance across a wide range of frequencies and incident angles. Such structures are easy to fabricate in thin semiconductor films by lithography and dry etching, and may find potential application in solar cells, bolometric detectors and thermal imaging devices.

Based on transformation electromagnetics concept, the design procedure of a lens antenna, which steers the radiated beam of a primary source, is presented. Laplace’s equation is adopted to construct the mapping between the virtual space and the physical space. Full wave simulations are performed to validate the model. The numerical results show that, when placing the lens antenna above a microstrip patch array, the radiated beam is deflected to an off-normal direction.

In this paper, the wakefield response of a dielectric Bragg waveguide (DBW) driven by an electron bunch is reported. Starting from the theory for planar Bragg reflectors, an analytical approach to designing this structure is derived. The DBW has applications as high-power THz radiator and for high-gradient acceleration.

<p> Excitation of plasmon resonance on the copper film deposited on fiber with tilted Bragg gratings is experimentally observed. It is shown that within several hours plasmon resonance undergo red shift and it with significantly increases. Both effects may be explained by oxidation processes. The time of plasmon copper film degradation has been measured. The possibility of implementation of copper as plasmonic material for refractive index measurements is discussed.</p>

<p> Plasmonic cavities and nanoantennas can strongly modify the excitation and decay rates of nearby emitters by altering the local density of states. Here, we demonstrate large enhancements of fluorescence and spontaneous emission rates of dye molecules embedded in plasmonic nanoantennas with sub-10-nm gap sizes.</p>

<p> We demonstrate a method to extract absorption and scattering from phase and intensity measurements of extinction from a single optical nano-antenna by developing a novel spectrally resolved interferometer integrated within a confocal microscope.</p>

<p> Transformation optics has proved a valuable tool in the study of plasmonic systems.Here we report on a new field of application: Electron energy loss spectroscopie for plasmonic nano-particles.</p>

Directional and circularly polarised emission from quantum dots coupled with chiral Ag nanostructures has been demonstrated. The far-field emission from the quantum dots coupled to the chiral nanostructures displays directionality in the emission pattern and more than 17% circular polarisation, following the handedness of the chiral structure.

Silver metal nanobox arrays are used to demonstrate plasmon-enhanced non-radiative energy transfer from an InGaN/GaN quantum well to a ~80 nm thick layer of CdSe/ZnS quantum dots embedded in PMMA. Three arrays of varying periodicity are fabricated by helium-ion lithography. Plasmon-enhanced non-radiative energy transfer efficiencies up to 30% are observed.

The influence of the layer eccentricity on resonances in active silver-core/silica-shell particles is reported. The super-resonant states of the concentric cases are significantly influenced by eccentricity, this being more profound for the larger cores. Slight displacements of the core and shell parts in these particles are likely to occur in standard fabrication processes, justifying the relevance of the results.

<p> We study theoretically the propagation of a surface plasmon polariton(SPP) propagating along the interface between air and a semi-infinite metal region consisting of two metals with a periodically modulated interface between them. Such a structure reveals asymmetric transmittance for a SPP incident on it from opposite sides. This asymmetric transmission of a SPP is based on the suppression of the 0-order SPP Bragg beam while the diffraction efficiencies of the +1 and -1 Bragg beams which do not satisfy reciprocity can be modified by varying the lattice constant of the grating and/or the angle of incidence. We predict this property of the structure by using a theoretical thin phase screen approach and confirm it by computer simulation calculations.</p>

<p> The ubiquitous spin-orbit interaction destroys the rotational symmetry of particles’ spin degree of freedom and introduces a universal transverse spin current regardless the particle nature of an electron or photon. Here we show that an optically thin metasurface with a rapid phase gradient over the wavelength scale refracts light anomalously and supports negative photonic spin Hall effect when a light beam is negatively refracted. The position-sensitive measurement reveals a broadband transverse motion of circularly polarized light through the symmetry breaking metasurface even at normal incidence. Moreover, we will show how the inversion symmetry in the 2D metasurfaces plays a role and generates a new type of photonic Hall effect.</p>

A broad class of metasurfaces comprised of periodic arrays of sub-wavelength interwoven multifilar spiral shaped strips and slots in conducting screens is considered. Their distinctive features are illustrated in the context of applications to frequency selective and high impedance surfaces and to voltage controlled reconfigurable metasurfaces.

<p> We bring evidence for the mechanism of direct excitation of dark mode in a double-layered structure consisting of Z-shape atoms enantiomeric metasurfaces separated by a dielectric. The electromagnetic behavior of such structure is investigated in the microwave regime. Depending on the orientation of the polarized electromagnetic field with respect to the Z atom topology and the incident plane we demonstrate direct field coupling excitation of quadripolar electric mode as well as dipolar and quadripolar magnetic modes. The proposed approach provides more flexibility in engineering dark mode resonances.</p>

We show experimentally that wavefront - the direction, spectral composition and phase profile of light emission - stimulated by free electron injection into plasmonic and dielectric media can be controlled with high finesse using holographic nanostructures.

<p> We present our recent work on dielectric metasurfaces for phase, amplitude and polarization control. The control over the properties of light can be achieve by controlling the retardation of a subwavelength periodic structure or by controlling the resonances of nano beams in semiconductors. We discuss approaches for achieving broadband retardation of light by tailoring the dispersion properties of the metasurface. Both guided mode and free space configurations are considered.</p>

We provide experimental evidence that waves can be anomalously localized, in relation to the standard Anderson localization, by introducing random configurations of the disorder that follow a distribution with a power-law tail, i.e., a Lévy-type distribution. Using a microwave waveguide with dielectric slabs randomly placed, we show that if the spacing between slabs follow a Lévy-type distribution, unconventional properties in the microwave-transmission fluctuations appear, revealing the presence of anomalous localization. Our analytical model describes the experimental results.
Media link(s):

See

 F. Falceto and V. A. Gopar, ``Conductance through quantum wires with Lévy-type disorder: Universal statistics
in anomalous quantum transport''  Europhysics Letters vol.  92, p. 57014, 2010.

A. A. Fernandez-Marin, J. A. Mendez-Berm\'udez, J. Carbonell, F. Cervera, J. Sanchez-Dehesa, and V.  A. Gopar
``Beyond Anderson Localization in 1D: Anomalous Localization of Microwaves in Random Waveguides,'' Physical Review Letters, vol. 113, p. 233901, 2014.

In anechoic chambers, the quality of RCS measurements is limited by couplings with the walls. In this work new calibration targets are introduced to assess these couplings. The idea is to get null monostatic RADAR Cross Section at some desired frequency by designing suitable plasmonic coatings. Such coatings are obtained on a metallic object by performing periodic grooves. They are thus an interesting alternative to standard RADAR Absorbing Materials whose constitutive parameters are not always well-known. Under a rotational symmetry assumption, very accurate RCS computations are possible up to several tens of GHz.

A low-cost ultra-thin design (< 5% lambda0) of microwave absorbing material is presented for easy implementation by printed electronics techniques. It consists of a resistive ground plane coated on one side of a flexible polyethylene terephthalate (PET) sheet and printed on the other side a perforated resistive film, respectively with thicknesses of 100 µm, 250 µm and 100 µm. A square lattice of holes is used for the perforation which allows the absorber’s partial transparency for visible light. With a conductivity of 80 S/m for the resistive films on both sides of the PET substrate, the design gives microwave absorption of more than 50% from 20 GHz to 56 GHz. The good absorption is valid over a wide range of incidence angles, in particular up to 70 degree for a narrow frequency band from 25 to 30 GHz.

A systematic investigation regarding the efficiency of a new wireless power transfer (WPT) system, which incorporates metamaterial building blocks as its fundamental resonators, is comprehensively pursued in this paper. The proposed configuration exhibits a significant improvement of the power delivered to the load as well as a promising minimization of the interaction with adjacent devices.

Capacitor-Connected Grids (CCG) are a recently developed structure, in which additional electric coupling is introduced to conventional purely magnetically coupled magneto-inductive waveguides (MIW). This overcomes the limitation on coupling strength from conventional MIWs. CCG’s potential to be used as ultra-wide band data transfer channels has been demonstrated in previous studies. This paper explores the possibility for using CCG as a power transfer channel by studying terminal matching conditions which can give the optimum power transfer efficiency. The result shows that the matching condition found in this study allows the optimal power transfer efficiency limited only by attenuation.

<p> We study theoretically magneto-inductive waveguides made by defect lines in metamaterial surfaces that comprise coupled split-ring resonators. The defects are introduced by changing the resonant frequency of the rings. We derive the wave dispersion relation and show how its properties depend on the sign and the strength of the inter-element coupling and the relationship between the resonant frequencies. We also demonstrate wave propagation along a 90-degree waveguide bend. The results show potential for novel planar magneto-inductive components.</p>

<p> The experimental demonstration of the total absorption of electromagnetic P-waves impinging on a low-loss dielectric thin layer covering a patterned metallic surface is here reported. A semi-analytical model has been employed to design a metallic grating of coaxial cavities that enhances the absorbing properties of the dielectric thin layer covering the surface. The experimental characterization of three samples shows that total absorption peaks are obtained at the frequencies predicted by the model. It is also demonstrated that the peak position is tunable with the cavity length.</p>

<p> We present the theoretical and numerical analysis of lasing action in a surface plasmon distributed feedback laser. We find a lasing threshold and other characteristics of the surface plasmon laser. Our calculations demonstrate that for certain parameters the lasing threshold nonmonotonically varies with the losses in the optical cavity.</p>

This paper reports a simple experimental demonstrator for investigation of non-Foster-based tunneling in radio-frequency regime. Demonstrator is based on a TEM transmission line with blocking screen, aperture of which is loaded with negative capacitors. This system shows stable broadband tunneling within 1:7 bandwidth (200MHz – 1400 MHz).

This paper proposes a new method to design negative capacitors by utilizing a parasitic reactance of an operational amplifier. The proposed method can provide a stable broadband negative capacitance. From the circuit simulation, a negative capacitance from -304pF to -275pF is yielded from 37MHz to 100MHz.

A digital discrete-time approach is presented for the design of two-port non-Foster circuits. This digital approach offers the potential for effective implementation of complex non-Foster circuits in applications such as wideband metamaterials, broadband impedance matching, and artificial magnetic conductors. A discrete-time implementation of a floating two-port negative capacitance is considered.

The design of a fast-wave microstrip line is presented, where digital discrete-time non-Foster circuits replace analog negative capacitance circuits. In such fast-wave lines, non-Foster approaches can overcome dispersion and bandwidth limitations. The proposed digital non-Foster approach is shown to offer broadband fast-wave performance, even with limited quality factor.

Active or intelligent materials whose properties are governed by an external stimulus have been used for many application including memories, opto-electronic devices, smart windows, drug delivery, bio-analytics, and surgery, amongst others. Not only transition metal oxides, semiconductors, and smart polymers have been shown to be applicable as switchable materials, molecular switching elements attracted the attention for the same purposes, too. In particular, molecule–plasmon interacting systems are very promising alternative to replace traditionally used active compounds. Combination of great potential of photo-active molecules with astonishing capability of plasmonics could open up new way in smart materials. In a molecule–plasmon hybrid system, the plasmonic resonance peak can be adjusted (shifted, split, or its intensity can be tuned) through the externally induced changes in the molecule. Although this concept has been widely explored, the application oriented approach is still missing. Recently, we have demonstrated that combination of the absorbing character of the photo-switchable dye molecules and plasmon resonance allows realization of a novel type of optical system, wherein the optical transparency can be manipulated by illumination. Visibly irradiated polymer doped spirooxazine which covered the thin metal film shows high transparency (higher than the intrinsic transparency of bare metal film) while UV exposure of the samples immediately turn the sample opaque. High electrical conductivity of the metal film and molecular induced transmission enhancement of the film enables us to have a transparent conductive metal with controllable optical transparency (smart material). With the same strategy, we also have shown that an optically driven perfect absorber can be developed in a multilayer films with few 10th of nanometer thickness. In such system, the reflectivity (absorption) of the metal mirror could be dropped down (increased) to a few percent (100%) or recovered to more (less) than 95% (5%) dynamically by UV or visible illumination, respectively.

This paper briefly reviews state of the art of gain-based and non-Foster-based active metamaterial structures with an emphasis on their underlying physical principles and pros and cons in real-world engineering applications. Several examples of new ideas based on bianostropic, non-reciprocal, and stable all-negative systems, are highlighted and discussed.

Many conventional optoelectronic devices consist of thin, stacked films of metals and semiconductors. In this presentation, I will demonstrate how one can improve the performance of such devices or obtain new functionalities by nano-patterning the constituent layers at length scales well below the wavelength of light.

<p> We present a study of lasing phenomena in geometries where feedback is provide by diffractive plasmonic particle lattices, and where a 2D polymer layer doped wit Rh6G provides gain and a 2D waveguiding environment. The strong feedback per particle makes this lasing system extremely robust to disorder. We study lasing upon removal and displacement of particles, as well as in quasiperiodic and aperiodic lattices.</p>

<p> A tunable plasmon-fluorescent elastic pad was realized using a Polydimethylsiloxane(PDMS) template covered with gold-nanoparticles(GNPs) and Rhodamine 6g. By increasing the size of particles, through chemical growth processes, and by applying mechanical strain, we found a red-shift of plasmon resonance, an increasing of fluorescence and Raman signal.</p>

We demonstrate the robustness of Dirac points against structural disorder in one-dimensional photonic nanostructures, by showing that even very high levels of disorder are unable to localize the modes located near the Dirac points. Both mode analysis and direct beam propagation simulations have been used in our analysis.

The resonant enhancement of magneto-optical effects in the case of hybrid plasmonic-waveguide modes excitation in magnetoplasmonic crystal with palsmonic patterns was experimentally demonstrate. The plasmonic pattern allows the excitation and additional field localization within nonmagnetic Bragg mirrors beside the rare-earth iron garnet microresonator layer. The Faraday effect increases by about 50% while the transverse magneto-optical Kerr effect demonstrates the several times enhancement with respect to the case of the bare magnetophotonic crystal. The angular dependences of the resonances’ spectral positions are in good agreement with the analytical equation for waveguide modes’ dispersion.

We present a novel type of the surface plasmon resonance sensor that is based on the magnetophotonic plasmonic heterostructure. The sensitivity of such sensor is enhanced by several orders of magnitude due to the excitation of the ultralong-range propagating surface plasmon polaritons in specially designed 1D photonic crystal coated with a magnetic layer. The sensing process was experimentally demonstrated for different concentrations of ethanol vapors in air.

We introduce a metamaterial for realizing true electromagnetically induced transparency (EIT) in analogy to atomic EIT effect. In the metamaterial, two resonant modes oscillating at different resonant frequencies are coupled through three-wave mixing in the presence of an auxiliary wave, and sharp transparency attributed to EIT effect is induced. We experimentally demonstrate the EIT effect using the metamaterial loaded with nonlinear capacitors in microwave region.

Superconducting tunable left-handed (LH) transmission lines can be manipulated by changing the phase of a microwave signal. The LH transmission line that we study is a chain of up to 20 planar cells containing Josephson junctions as fixed compact inductors and shunting SQUIDs as magnetically tunable inductors. Harmful effect of both standing waves and RF leak are being reduced using a high-ratio wideband impedance transformer from 50 Ohm to 5 Ohm within frequency range 6-12 GHz (return loss < 1.5 dB) integrated in the same chip. The possibility to tune the regime from left- to right-handed operation at fixed frequency is clearly demonstrated.

Complete absorption of light which has been recently demonstrated in metamaterials has drawn the attention of the scientists because of its potential application in harvesting energy and sensors. Controlling the absorption band-width, peak position and intensity are some of the essential factors in metamaterial absorbers. Although many reports showed the metamaterial with high absorption in broad range of spectrum, strong tuning the absorption band-width has been rarely shown. In this work, we show that using three component (Au, TiO2 and SiO2) nanocomposite deposited on an optically thick gold film through simultaneous sputtering, one can broaden the band-width and peak position to span UV up to NIR.

We characterise the optical, mechanical and acoustic properties of a medium through a theoretical examination of the electrostriction constant of both conventional dielectric materials, metals, and composites. The objective is to investigate whether one can construct metamaterials which exhibit tuneable electromechanical properties, for the purpose of engineering enhanced stimulated Brillouin scattering (SBS).

Transparent conducting oxides have received significant attention in recent years for their tunability. Here, we study the tunability in the static optical properties of TCO films and nanostructures, as well as their dynamic properties under optical pumping. Combined with their low-temperature and CMOS-compatible processing techniques, TCOs are shown to be key materials for future dynamic nanophotonic devices.

Through the transformation acoustics theory we derive the constitutive parameters of the arbitrary shapes cloaks working in complex media. And a unidirectional acoustic cloak for layered background is designed and realized with homogeneous metamaterials.

Thin plates engineering has recently raised strong interest as they offer the possibility to curve wave trajectories, cloak macroscopic objects, or focus flexural waves by negative refraction without a negative refractive index. Here we review our recent results and present several approaches to structure plates and control elastic wave propagation.

Using rigorous transfer matrix theory in combination with Wavelet Transform Modulus Maxima analysis of multifractal signals, we demonstrate all-dielectric metamaterial structures that exhibit photon transport properties widely tunable across a broad spectral range.

Inspired by the acoustic Helmholtz resonator, we propose a slit-box electromagnetic nanoantenna able to concentrate the energy into a deep subwavelength volume. This design gives birth to giant field intensity enhancement throughout the slit. The resonance itself exhibits unusual properties which could be of great interest for applications requiring extreme light concentration.

We propose a new type of chiral optical interactions based on a low-dimensional polarization eigenstate. Directional coupling between different spin momentum of light leads to the convergence of polarization states to the singularity point. For its meta-material implementation, we use parity-time (PT) symmetric potentials in a polar meta-molecule platform to achieve the unidirectional energy transfer in polarization space.

We present the first observation of circular dichroism due to a combination of resonant toroidal dipole and electric quadrupole excitations in a toroidal metamaterial.

We study optical properties of subwavelength arrays of 3D-chiral metal holes ex- hibiting extreme circular dichroism and optical activity. The nanoscale shape features resolved by atomic force microscopy were processed with the developed AFM-to-FDTD data pipeline for reconstruction, averaging and preparation of the hole shape for FDTD simulations. The simulation results point unambiguously at the chiral localized plasmon resonance as the cause of extreme optical chirality.

<p> A bilayered chiral metamaterial is proposed and experimentally demonstrated to exhibit polarization mutual conversion of linearly polarized electromagnetic waves. Simulated and measured results show that the polarization mutual conversion can be well engineered by structural parameters.</p>

<p> We demonstrate the data transmission of 10 Gbit/s NRZ optical signal through a long-range dielectric-loaded surface plasmon polariton waveguide. The BER penalties do not exceed 0.6 dB at few mW of received optical power.</p>

We study scattering of H- and E-polarized electromagnetic vortex Bessel beams in the infrared range by a gyrotropic cylinder constituted from graphene-sandwiched dielectric disks and located in free space in the case where the symmetry axes of the beam and the cylinder coincide. Significant enhancement of the beam scattering is found to occur if the topological charge and frequency of the vortex Bessel beam are equal to the azimuthal index and frequency of the cylinder multipole resonance, respectively.

We report on developments in fabricating nano and micro-structured volumetric plasmonic materials and metamaterials utilizing crystal growth techniques as the micro-pulling down method. Materials developed by directional solidification of eutectic composites and directional solidification of dielectrics nonchemically doped with functional nanoparticles.

We discuss our recent work on color printing using metal nanostructures in Au, Ag, and Al. Strategies to achieve color mixing and 3D stereograms with this new method of structural color will be presented.

A systematic procedure for designing bianisotropic metasurfaces is outlined, and a pragmatic approach to realizing them using cascaded anisotropic electric sheets (patterned metallic surfaces) is presented.

In this paper, we propose a novel approach based on the mantle cloaking method to reduce the mutual coupling between closely spaced planar antennas. We consider two microstrip-fed monopole antennas resonating at slightly different frequencies and show that by covering each antenna with a conformal elliptical metasurface formed by conformal and confocal printed arrays of sub-wavelength periodic elements partially embedded in the substrate, the antennas become invisible to each other and their radiation patterns are restored as if they were isolated.

<p> We propose to synthesize a parametric metasurface whose transmission properties are modified by illuminating a control electromagnetic wave on the structure, in the same way the channel conductance of a transistor is controlled by a gate signal. We present a general solution of the problem that yields analytical expressions for the synthesized metasurface susceptibilities. It turns out that such a problem generally violates reciprocity conditions, indicating the necessity of nonreciprocal elements. Nevertheless, we propose here a reciprocal parametric metasurface based on the destructive interference of transmitted waves corresponding to the initial signal wave and the control wave, respectively, at the cost of parasitic reflected and transmitted fields.</p>

We propose a highly-efficient yet simple metasurface design comprising of a single, anisotropic trapezoid-shape antenna in its unit cell, which could achieve broadband (450 - 850 nm) anomalous reflection and spectrum splitting at visible and near-IR frequencies with high conversion efficiency. Such beam splitting has been experimentally visualized using a CCD camera and free space, angle-resolved measurement setup.

<p> It is demonstrated that cross-polarization effects for metasurfaces can be fully controlled by rotating the metasurface or equivalently the polarization state. It is possible to remove the cross-polar coefficients. Also, it is possible to find the orientation for which the cross-polar coefficient takes the maximum value.</p>

It has been recently shown that a metasurface presenting a phase-gradient can be effectively used as a partially reflecting surface (PRS) in a Fabry-Perot leaky wave antenna to produce beam steering. The aim of the present contribution is to develop and present an analytical model which will allow us to predict the angle of deflection.

We propose a novel method for a direct retrieval of electric and magnetic coupling coefficients in metamaterials with an arbitrary type of inter-element coupling. The proposed technique employs a transformation of the frequency dependence of complex current amplitudes in interacting meta-atoms, enabling separate deduction of the magnetic and electric coupling coefficients. The method is verified on a number of examples using both experimental and simulation data in a wide frequency range from MHz to THz. Our approach is valid for elements of arbitrary shape and should be useful for design of metamaterial structures that employ slow waves of inter-element coupling for manipulation of the near field.

Analysis of instantaneous and time-average Poynting vector produced by a dimer of coupled meta-atoms is performed with the aim of providing insights into the formation of superdirective radiation by metamaterials. Visualisation of the superdirectivity is further supported by studies of the shape of causal surfaces separating the reactive and radiated power and their space-time diagrams.

In this contribution, we present the design of a power-selectivity horn filtenna based on the use of a nonlinear Split Ring Resonator (SRR). In particular, in order to obtain a nonlinear behavior of the SRR, we load its external gap with a pair of Schottky diodes, which require a not negligible power level to be activated. Inserting the resulting nonlinear resonator inside the throat of a horn antenna, we show that both matching and radiating properties exhibit or do not exhibit a notched-band, depending on the operating power level.

The juxtaposition of materials having positive and negative effective properties allows the attainment of electrically small resonators. It has been demonstrated that these miniaturized resonators, as near-field resonant parasitic (NFRP) elements, facilitate the realization of electrically small radiators (antennas) and scatterers. A variety of metamaterial-inspired NFRP configurations from microwave to optical wavelengths will be used to illustrate the associated design concepts and their advantages in practical applications.

Fishnet structures provide a popular procedure to obtain negative-refraction-index artificial media. They are basically stacked extraordinary-transmission structures that are closely spaced. Thus these structures can be built by combinig two or more metallic plates with a 2D periodic distribution of small apertures. Analytical models based on equivalent circuits are almost trivially obtained when the electric separation between metal plates is relatively large. However the more interesting situation arising from tightly coupled screens is more involved and only heuristic equivelent-circuit approaches have been reported in the literature. In this contribution a systematic approach to obtain a general circuit model for this kind of structures is developed.

In this paper, an algorithm that allows to design bianisotropic metafilms with given spectral properties is proposed. It is based on the analytical approach and can be easily integrated with natural experiment. Using the algorithm, it is possible to account for statistical straggling of the constituent meta-atoms' geometric parameters.

The reflection/transmission coefficients are calculated for the hyperbolic metamaterial slab are calculated using the 4x4 Berreman matrix method for arbitrary orientation of optical axis according to slab boundary. Gain or losses in the medium are described as imaginery parts of the components of dielectric tensor of the medium. The threshold conditions for gain and radiation angle were calculated for given losses and axis orientation.

Maxwell's differential equations are used to find a set of three boundary conditions for the interface between free space and an electric quadrupolar continua satisfying a physically reasonable constitutive relation which allows both a propagating and evanescent wave in the continuum (thereby requiring three boundary conditions to determine a unique solution for an incident plane wave).

Solid metal films are opaque over the whole frequency spectrum due to the high density of free electrons. Even at microwave frequencies, thin metal layers with thicknesses well below skin depth reflects most of the impinging electromagnetic energy. However drastical enhancement of the transparency has been reported using resonance phenomena within a narrow frequency band. This contribution provides an analytical circuit model that explains the recently reported strong transmission in terms of relatively simple circuit theory grounds.

Reversible, optically-induced surface metallization in a nanoscale layer of elemental gallium forming the backplane of a photonic metamaterial absorber provides a mechanism for a strong, resonantly enhanced reflective optical nonlinearity at μW/μm^2 intensities.

We investigate second-harmonic generation from arrays of metal nanoparticles as a function of the incident angle of light into the structure. The generated signal is significantly affected by the surface-lattice resonances of the structure.

Buckling of beams under uniaxial loading is perhaps the most basic example of an elastic instability. Its textbook explanation rests on Euler's elastica, which describes the bending of elastic lines. In this talk we show by means of experiments, simulations and theory that sufficiently wide beams exhibit discontinuous buckling, an unstable form of buckling where the post-buckling stiffness is negative. In particular, we will identify nonlinearity as the main cause for negative stiffness. We develop a 1D model which generalizes Euler's elastica to account for nonlinearities, and show that it matches our experimental and numerical data. Inspired by the central role of nonlinearities in this model, we then utilize this non-linearity to create metamaterials that allow us to rationally design the negative post-buckling stiffness of metabeams, independently of beam thickness. We will show that metabeams, beams that are formed by patterns of elliptic holes, can exhibit strong nonlinearity. We demonstrate that for sufficiently strong nonlinearity, we observe discontinuous buckling for metabeams as slender as 1\% numerically and 5\% experimentally. This makes it possible to violate Eulers limit for slender beam buckling.

<p> We propose to use hysteresis in a 1D system of active nonlinear nanoresonators to achieve the Narrowband Resonances. Combination of Wood anomaly, retardation, and nonlinearity provides platform for light nanosources and highly sensitive sensors.</p>

We demonstrate nano-opto-mechanical metamaterial with a cubic optical nonlinearity that is seven orders of magnitude greater than the reference nonlinearity of GaAs. The nonlinearity is driven by light-induced deformation of the plasmonic nanostructure.

We demonstrate a few novel small-footprint and broadband integrated photonic devices based on optical waveguides patterned with phased antenna arrays. These devices include waveguide mode converters, polarization rotators, perfect absorbers, and optical power diode.

We present an experimentally demonstration of an all-dielectric silicon-based metasurface that possess a sharp Fano-resonance. Due to extremely low absorption loss and coherent interaction of neighboring meta-atoms, a Q-factor of 483 is observed. We also show that the metasurface can be utilized for significantly enhancing nonlinear conversion.

<p> It is demonstrated that self-complementary zig-zag screens can be used for designing circular polarizing beam splitters. Although there is only an exact frequency at which the aspect ratio is 0dB, it is shown that the relative bandwidth for deviations within ±3dB can be as big as 68%. Besides the periodicity is deeply subwavelength what reduce the diffraction.</p>

Metasurfaces for realization of L-C circuit elements are presented. Novel combinations will engineer light spectrum to interest, to have multi, broad, or dispersion-less frequency spectra. Three unique designs are investigated, a diplexer from patterned surfaces, a wideband nanofilter where the frequency band is desirably controlled, and a dispersion-less metasurface

The Thomson Reuters Web of ScienceTM lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas.

Metasurface 2D leaky-wave antennas exhibiting rotationally invariant electromagnetic features. Moving from structures based on metal strip gratings, the talk will address planar structures that include omnidirectional homogenized metasurfaces, considering in particular antennas based on metal patterned screens, possibly loaded with additional wire-medium layers, and on electrostatically biased graphene sheets.

The design of a higher gain embroidered antenna using the resonant cavity concept is presented. The patch as the main radiator and the partially reflective surface (PRS) structure as the superstrate are realized using an industrial embroidery machine. The PRS consists of periodic cross-slots (9 x 9 unit cells) in order to have a durable embroidered structure. The ground plane is made of a conductive woven fabric. The fabricated antenna has a relatively broad 1 dB-gain-bandwidth (10%) and a directive pattern (3 dB beam-width of 40° at the center frequency). Despite the higher losses in the conductive thread due to the resonant cavity effect, this antenna has a maximum realized gain of 6.8 dBi, which is typically 3 to 6 dB more than other embroidered single patch antennas.

We introduce new microgap thermophotovoltaic systems enhanced by tungsten nanowires and allowing the optimized super-Planckian spectrum of radiative heat transfer for electricity generation. We perform a system analysis of these systems.

We demonstrate experimentally that plasmonic nanoantennas made of metal-insulator-metal patches can be used to tailor the spectral emissivity of a gold surface in the infrared. Several areas of a gold mirror sample were covered with various geometries of nanoantennas. Their emissivity was characterized thanks to a dedicated bench, based on the combination of a Fourier transform spectrometer and an infrared camera. A polarized monochromatic emission, tunable depending on the geometry of the patch, is obtained, which is coherent with the theoretical predictions.

<p> Using uniaxial double negative metamaterials it is possible to create bodies which optimally absorb power from all spatial harmonics of the incident fields, both propagating and evanescent. Comparing with the ideal black bodies these new objects appear ``infinitely more black''. The concept is illustrated by considering infinite absorptive cylinders.</p>

<p> All-optical processing of signals is one key milestone that needs to be achieved for eliminating the disadvantages of optical–electrical–optical conversion, thus moving towards terabits per second communications, high-performance computing and signal processing. All-optical modulation means control of the phase or intensity of one light beam by another. Here we demonstrate a sub-wavelength plasmonic metamaterial performing as an ultrafast, broadband and energy efficient (single photon) all-optical switch.</p>

We show that the nonreciprocal surface waves supported by biased ferrites at microwave frequencies can be harnessed to develop metamaterials that break time-reversal symmetry. We illustrate these ideas by designing a metamaterial one-way glass in the S band of the electromagnetic spectrum.

<p> We discuss some of our recent works in understanding optical reciprocity without the use of magneto-optics. A key objective for optical non-reciprocal device is to provide optical isolation. We show that a large class of nonlinear optical isolators in fact is constraint by a dynamic reciprocity, and therefore cannot provide complete optical isolation. We also discuss topological effects in dynamic-modulation-induced optical non-reciprocity.</p>

We propose a low scattering metal/dielectric layered nanotube of which size is comparable to incident wavelength. The analysis of light scattering shows that the layered nanotube can be described as a radial anisotropic hyperbolic metamaterial. In addition, we show that the low scattering of the layered nanotube occurs when the effective permittivity in the angular direction is nearly zero. The results will be useful for designing invisible nanotube applications.

A particle scattering in close proximity to an anisotropic substrate can experience a repulsive force if one of the diagonal components of the permittivity tensor is close to zero. We derive a condition for this repulsive force and show its broad bandwidth for realistic metamaterial substrates, including those based on graphene multilayers.

Photonic hypercrystals represent a new class of artificial optical composites, that has the properties of both the metamaterials and the photonic crystals, as well as some new features not found in these media. In particular, the hypercrystals support an even number of Dirac dispersion cones that originate from the Motti topological transition. The resulting singularity in the photonic density of states has a strong effect on the emissivity of the hypercrystal.

<p> Passivity is used to derive physical bounds on metamaterial devices. The bounds are determined from sum rules or optimization problems involving the stored energy. They typically relate some product between the performance and the bandwidth. The sum rules are computed from the low and/or high frequency response of the system. The corresponding stored energy is determined from a state space representation of the passive system. An overview of physical bounds for metamaterial applications such as scattering, antennas, absorbers, high impedance surfaces, and extra ordinary transmission is presented.</p>

Put your abstract here

Electromagnetic pulse propagation in a quantum metamaterial - artificial, globally quantum coherent optical medium - is numerically simulated. We show that a one-dimensional quantum metamaterial based on superconducting quantum bits, initialized in an easily reachable factorized excited state, demonstrates lasing in microwave range, accompanied by the chaotization of qubit states and generation of higher harmonics. These effects may provide a tool for characterization and optimization of quantum metamaterial prototypes.
Media link(s):

See http://arxiv.org/abs/1412.4464

Superconductor/polymer composites can offer specific functionalities in metamaterial devices by taking advantage of unique electromagnetic properties. Methodologies have been developed for fabricating superconducting/polymer composites by casting and 3D printing. Permittivity and permeability values at 298K and 77K have been correlated with the homogeneity and density of YBCO distributions in the polymer.

We report on the discovery of a new type of optical plasmonic media: by observing absorption lines in a superconducting metamaterial out of Nb, we find that the Nb metamaterial shows plasmonic properties at visible wavelengths. This suggests that superconductors are a feasible platform for new generation of plasmonic metadevices.

Metamaterials made up of Radio Frequency (RF) Superconducting Quantum Interference Devices (SQUIDs) can display strongly nonlinear behavior over a range of parameters, including dc flux and rf power. We have discovered that coupled arrays of rf SQUIDs have self-induced broadband transparency due to a qualitatively novel nonlinear mechanism.

One of the great challenges of metamaterial homogenization resides in the computation of the reflection and transmission coefficients at interface with air. We propose a scalar product for which modes are naturally orthogonal for lossless metamaterials invariant along one direction of space. It paves the way to exact projection of excitation into propagative modes without computing the evanescent ones.

<p> We have developed an analyticalmodel to describe spoof surface plasmon polaritons at optical wavelengths in a metallic grove array structure. Based on the model and numerical calculations, a band gap for spoof surface plasmon polaritions is predicted to exist at optical wavelengths. By introducing a defect, we demonstrate subwavelength scale localization of spoof surface plasmon modes which have a strong toroidal dipole moment.</p>

<p> Tunability is a crucial requirement for the development of many future metamaterial-based technologies. Here, we show the design, the fabrication, and the characterization of an actively tunable, self-assembled metamaterial. The material is composed of silver nanoparticles covered with a liquid crystal that shows a pronounced thermal response, making it suitable for controlled tunability. This is possible since the nanoparticles spatially distribute in different configurations depending on the temperature. This strongly influences the optical properties of the material. The entire process is reversible and the optical response reproducibly changes across many cycles. The presented method paves the way for many future applications of tunable metamaterials in the visible region.</p>

In this paper, we demonstrate that a wire medium (WM) slab loaded with graphene-nanopatch metasurfaces (GNMs) enables the enhancement of evanescent waves for the subwavelength imaging at terahertz (THz) frequencies. The excited surface plasmons at the lower and upper GNMs are coupled by an array of metallic wires. The dual nature (capacitive/inductive) of the GNM is utilized in order to design a dual-band lens in which the unique controllable properties of graphene and the structural parameters of WM slab provide more degrees of freedom in controlling two operating frequency bands. The lens can support the subwavelength imaging simultaneously at two tunable distinct frequencies with the resolution better than λ/6 even if the distance between GNMs is a significant fraction of wavelength (> λ/5.5).

We have been exploring a variety of scenarios as “extreme platforms” for light-matter interaction. This includes extreme dimensionality as in metasurface and metawire photonics, “static optics” in extreme-parameter metastructures, nonreciprocity in extreme near field, and signal processing at the nanoscale, just to name a few. In this presentation, we will present some of our most recent results on these topics.

We discuss tunable nanoantennas with resonances dominated by higher order electromagnetic multipole moments, by resonances that couple the electric and magnetic response, or even just by multiple spectrally interfering electric dipolar resonances. These antennas can provide novel functions as isolated elements or once arranged in an array.

We demonstrate efficient transmission of optical power between two optical nanoantennas in a wireless antenna link. By controlling the phase of the signal driving the elements in a nanoantenna array, we furthermore realize optical beamsteering. The phased nanoantenna array allows us to steer the wireless nanoantenna link to dynamically address different receivers.

<p> We demonstrate a single plasmonic element Fano nanoantenna allowing for strong directional coupling of light to a silicon waveguide depending on the operational wavelength. This antenna can spatially separate wavelength-encoded optical signals, realizing an ultra-compact plasmonic demultiplexer.</p>

<p> In this article, we perform temperature-dependent experiments on an ensemble of PbS colloidal quantum dots (CQDs) coupled with plasmonic nanoring arrays. We show that our measurements cannot be explained by standard theory that treats emitters as two-level systems and propose a new mechanism to account for these findings.</p>

Active control of three-dimensional configuration is one of the key steps towards smart plasmonic nanostructures with desired functionalities. We lay out a multi-disciplinary strategy to create active 3D plasmonic nanostructures, which execute DNA-regulated conformational changes on the nanoscale.

<p> The spontaneous emission properties of a light emitter can be significantly modified by an adjacent hyperbolic metamaterial. We investigate how to design a hyperbolic metamaterial to enhance the emission rate at a desired operational frequency. About two orders of magnitude enhancement of the spontaneous emission rate was achieved in experiments.</p>

In this work, we develop theoretical tools that allow an efficient optimization of the optical resolution of flat lenses made of hyperbolic metamaterials. Our results demonstrate that feasible structures made of silver and TiO2 layers focus visible sub-wavelength images. We in particular show that defect metallic layers introduced into metallo-dielectric multilayers increase the sub-wavelength focalization distance up to 2λ.

We report the experimental realization of an HMM in which a simultaneous epsilon near zero and near pole behaviour is found. Supercollimation effect, as well as the possibility of exploiting this device as a perfect lens in the visible range, has been demonstrated, reaching a lambda/8 resolution.

<p> We report on the progress of the physics and applications of flexible metamaterials in the visible range. In particular we describe the fabrication and optical properties of flexible plasmonic sensors for Surface Enhanced Raman Spectroscopy. We also report on our progress on the all optical manipulation of the membranes, both in microfluidics and the air environment.</p>

The split-ring resonator having a high quality(Q) factor using dielectric materials at microwave regime is proposed. To realize the high-Q resonator, impedance matching method is employed. According to the measured results, we find that the loaded-Q factor is about 1670 at the resonant frequency, 12.52 GHz.

Abstract – In this paper, both simulated and experimental measurements of asymmetric split-ring resonators (A-SRRs) with varying diameters are reported. Their responses appear in the mid-infrared (IR) spectral region, which matches well with the vibrational resonances of many organic molecules - and they could potentially be used to detect protein molecules in their native biological environments. The use of a ZnSe substrate allows transmission spectra to be measured at wavelengths in the mid-IR.

<p> We present recently obtained experimental and theoretical results with the 1D chains of optically coupled nanoresonators exhibiting ultra narrowband resonances. Ultrahigh sensitivity is expected to be enough for reliable detection of exosomal content for express selective cancer diagnostics.</p>

<p> We demonstrate a higher sensitivity by using asymmetric metamaterial structures, as compared with their symmetric counterparts. We find that measurement of the same quantity of analyte deposited simultaneously on arrays of symmetric and asymmetric metamaterial structures leads to a greater red-shift, based on the refractive index change (Δn) in the medium that surrounds the structure.</p>

<p> We present vertical split-ring resonators (VSRRs) which behave as magnetic metamolecules sensitive to both the incident electric and magnetic fields upon excitation. A couple of potential applications such as VSRR-based highly sensitive refractive-index sensor and metasurface for light manipulation in optical communication frequency will also be demonstrated.</p>

We demonstrate spatial and temporal control over metamaterial properties using coherent interactions of beams of light on plasmonic metasurfaces. This is illustrated by all-optical logical operations between two images.

<p> We utilized direct laser writing for the fabrication of plasmonic nanoantennas resonant in the near- and mid-infrared spectral range to investigate the impact of plasmonic coupling between neighbouring antennas on the enhancement in surface-enhanced infrared spectroscopy.</p>

Parity-time (PT) symmetry in an optical parametric amplifier, based on negative index metamaterial (NIM), is studied. Parametric amplification processes are considered in all the three regimes of PT symmetry, namely, below, at and above the PT threshold. It may be possible to exploit PT symmetry for various applications including compensation of loss in NIMs.

This paper reports the demonstration of a spectrally selective nanoelectromechanical system (NEMS) infrared detector based on an ultrathin plasmonic piezoelectric resonant metasurface. The combination of nanoplasmonic and piezoelectric electromechanical resonances enables strong and spectrally selective absorption of infrared radiation in an ultra-low volume NEMS resonator with high electromechanical performance and unprecedented thermal capabilities. These attributes lead to the demonstration of a high resolution (noise equivalent power of 2.1 nW/Hz^1/2), fast (thermal time constant of 440 μs) uncooled long wavelength infrared (LWIR) detector with ~80% absorption for an optimized spectral bandwidth around 8.8 μm. This demonstration marks a milestone towards the implementation of a new class of high performance, miniaturized low power IR spectroscopy and multi-spectral imaging systems.

We demonstrate experimentally that hyperbolic metamaterials fundamentally alter dipole-dipole interactions conventionally limited to the near-field. The effect is captured in long-range energy transfer and lifetime reduction of donor emitters due to acceptors placed 100 nm away.

<p> Hyperbolic metamaterials are anisotropic but very little has been done to admit any significance to the orientation of the optical axis. This is a very important aspect of wave propagation in such materials so setting up calculations in which the optical axis is assumed to lie only along one direction leads to completely incorrect conclusions.</p>

<p> In this work we show that a wire-medium hyperlens can be used for significant enhancement of radiation from small sources. This enhancement holds in the ultra-wide frequency band and can be used in numerous applications. We investigate how the divergence of metal wires and other design parameters modifies the radiated power of a dipole, comparing with an array of parallel wires, implement the optimized hyperlens in the microwave range and verify the theoretical results experimentally.</p>

Abstract – We report on the optical characterization of metallic nanowire (NW) metamaterials. In contrast to multilayer metamaterials, nanowire metamaterials exhibit an omnidirectional epsilon-near pole (ENP) and an angularly dependent epsilon-near-zero (ENZ), which are both highly absorptive resonances. We also demonstrate large tunability of the epsilon-near-zero resonance in the visible spectrum from 583 nm to 805 nm as the gold nanorod fill fraction changes from 26% to 10.5%. Energy dispersive x-ray (EDX) and X-ray Diffraction (XRD) analyses are used to ascertain the quality of electrochemically deposited Au nanowires prior to and after annealing.

<p> Graphene supports strongly confined transverse-magnetic sheet plasmons whose spectral characteristics depend on the energetic distribution of Dirac particles. When the carrier system is inverted by photo-excitation graphene plasmons can become amplified and are spontaneously emitted. With rates in the 10-100 fs range nonequilibrium plasmon (NP) emission provides an non-instantaneous channel for ultrafast carrier recombination whose impact on the carrier relaxation dynamics is here investigated together with optical phonon (OP) emission. Our theoretical results are in agreement with the experimentally observed hot carrier relaxation dynamics in photo-excited graphene.</p>

We propose to use the remarkable mechanical and optical properties of graphene monolayers to couple light and phonons via surface plasmons. This is a achieved by acoustically corrugating a graphene sheet and thus forming a diffraction grating that, under light illumination permits the generation of graphene plasmons with many intriguing properties. This efficient way of plasmons generation can be used for many applications ranging from Terahertz (THz) antennas, bio-chemical sensors, tunable invisibility cloaks and THz radiation modulation.

We demonstrate that manifestation of nonlinear magneto-electric interference in the wave mixing process can allow not only for directional, but also for a non-reciprocal nonlinear generation from nanoelements, with the direction of nonlinear generation decoupled from that of the excitation beams. When arranged in a periodic fashion forming a metasurface, the arrays of such non-reciprocal nonlinear optical antennas can give rise to a series of unique nonlinear phenomena, with an example of a non-reciprocal nonlinear imaging obtained using a process of difference frequency generation presented here.

The giant resonant excitation of the second harmonic of THz radiation in planar “dielectric – graphene – dielectric…” metamaterial is investigated. Oblique incidence of s- and p- polarized first harmonics is considered, using kinetic and hydrodynamic approaches. The reflection into the second harmonic reaches the values of 0.1 for intensities and more.

We proposed a microwave photonic topological insulator in non-bianisostropic photonic metacrystal waveguide with ε/μ-matching meta-atoms. Gapless pseudospin-momentum locked edge states and robust transport were experimentally observed. Dispersion-immune photonic topological insulators were realized by staggered photonic metacrystals.

We review our recent studies on chiral, switchable chiral, and bianisotropic metamaterials, and the possibilities that they offer for the control of THz and far-IR radiation. Employing such metamaterials, strong and switchable optical activity, asymmetric transmission, and asymmetric total absorption are demonstrated, both theoretically and experimentally.

We investigate the optical forces that arise when chiral metasurfaces are illuminated by circularly polarized radiation. Using the Maxwell stress tensor formalism we calculate the momentum transfer for several chiral designs and incident polarizations from full-wave numerical simulations. We relate chiral frequency-dependent resonances to a rich variety of optical forces.

The symmetry of a material plays a crucial role in polarization sensitive optical phenomena; it is therefore powerful to employ symmetry-controlled artificial nanostructures when developing devices to control the polarization of light. We have been developing methods to control circularly polarized light using such metamaterials. In this presentation, we show the recent progress made in our research on the control of circularly polarized light emission from chiral photonic nanostructures, active THz polarization control with MEMS spiral metamaterials and second-harmonic generation from a metamaterial with threefold rotational symmetry.

<p> We present mid-IR light concentrators based on a microstructured polymer film. The polymer thick film is microstructured as such to fine tune the effective refractive index profile throughout the polymer surface in order to efficiently focus light. Herein, we present simulated and experimental demonstration of the photonic design for a mid-IR light concentrator operating at a wavelength of 10 µm. FDTD simulations were realized in order to determine optimum structure parameters.</p>

We study plasmonic properties of metal nanoparticles with sharp corner- and tip-shaped surface perturbations supporting discrete plasmon resonances superlocalized on the scale of the curvature radius. We reveal the conditions for employing such particles as nano-antennas that precisely couple the free-space light to the nanosize volumes near the perturbation apexes with the light fields enhanced by several orders of magnitudes

<p> By combining the zoning technique with the strong dispersion of the fishnet metamaterial, a broadband fishnet diffractive optical element is designed, fabricated and measured at millimeter-waves. Diffraction-limited full width at half maximum ~0.8 wavelength is demonstrated experimentally when the focal properties of the lens are studied. Also, directivity of ~16.6 dBi is achieved when the fishnet lens is used in a lens antenna configuration together with an open-ended waveguide operating as a feeder</p>

We study the efficiency of several types of all-dielectric light-trapping and antireflective coatings for the enhancement of photovoltaic absorption in thin-film silicon solar cells. We compare the photovoltaic absorption enhancement offered by a square array of nanovoids in the dielectric covering of the cell with that granted by a flat blooming layer, and a densely packed array of dielectric nanospheres. The dependence of anti-reflection and light-trapping properties on the angle of incidence is numerically investigated, and it is shown that the array of voids keeps optimal also after averaging over the incidence angles.

We propose a novel design to enhance the directivity and power extraction of a dipole source. The design consists in a cavity-backed non-uniform partially reflective metasurface (PRM). The multiple reflections inside the cavity yield full transmission by way of constructive interference at the PRM.We show that by allowing the metasurface to be partially reflective, the realization constrains are relaxed compared to a design with a reflection-less metasurface.

Spectral, angular and spatial characteristics are calculated of flat lenses on the basis of layered Ag/TiO2 structures in ultraviolet light. It is shown that phase function of MD-structure allows determining not only its usefulness as a lens, but also focal distance. The equation of the lens is obtained for the common case when the media at the input and output are different.

<p> The interaction between an object and electromagnetic waves can be described in terms of its surface impedance. By introducing large anisotropy into artificial impedance surfaces, it is possible to achieve a high degree of control over this interaction that is not possible with isotropic surfaces. These surfaces can be used to create nonscattering surface waveguides, beam shifting structures, and to control scattering from edges and other features. With new patterning techniques we can obtain arbitrary and smoothly varying impedance functions for even greater control.</p>

<p> We present an analytical normalization procedure for resonances in periodic arrays of nanoantennas, which can be used to predict the sensitivity of resonances with respect to changes of the surrounding dielectric environment by first order perturbation theory.</p>

Straight graphene edges are known to completely reflect plasmonic modes. Here, however, we examine structured graphene edges, which provide the ability to tailor and even completely cancel the reflection. Interesting phase changes and resonances appear when longitudinal modes interact with transverse modes mediated by edge plasmons.

The ability to control the polarization state of an electromagnetic wave thanks to plasmonic metasurfaces is at the core of many various applications. We demonstrate both theoretically and experimentally that plasmonic planar L-shaped antennas can induce a 90°-rotation of the linear polarization of light with a nearly total efficiency in the mid-wavelength infrared. Then, in order to increase the bandwidth of the conversion, the combination of several L-shaped antennas in the same subwavelength period is explored.

We demonstrate control of light polarization with light, without nonlinearity. The manifestation of optical activity in a metasurface is dynamically controlled using the coherent interaction of light waves on the nanostructure to enhance and suppress the light-matter interaction. This enables ultrafast polarization modulation and highly sensitive detection of optical activity.

We experimentally demonstrated enhanced fluorescence of quantum dots by Fano resonance in optical metamaterials composed of asymmetric double bars (ADBs). ADB metamaterials hybridized with quantum dots dispersing in a polymer layer were fabricated and fluorescence at a wavelength of around 1350 nm was measured by a microscopic fluorescence measurement system. Fivefold enhancement of fluorescence from quantum dots by Fano resonance in ADB metamaterials was observed. Depending on a degree of asymmetry of ADB metamaterials, spectral shapes of enhanced fluorescence were modified.

An alternative mechanism to generate terajets at terahertz frequencies is demonstrated using 3D dielectric cuboids. The focusing properties of the terajets are evaluated for several cuboids of different dimensions. Also, the backscattering enhancement is evaluated using metal particles within the terajet region, demonstrating a maximum enhancement of 11.38dB for a gold particle of diameter 0.29λ0. Finally, multifrequency operation is verified at the fundamental and first frequency harmonics at sub-THz frequencies, demonstrating a good agreement with numerical results in terms of FWHMx.

Microsized carbon fibres exhibit strong resonant absorption at terahertz frequencies. Using near-field terahertz time-domain spectroscopy, we probe their conductivity by analysing the degree of field enhancement produced by plasmonic resonances. We demonstrate, theoretically and experimentally, the potential usability of carbon microfibres as terahertz absorbers with engineerable response.

We demonstrate a route to design structures exhibiting optical activity in general scattering directions. This means that when the structure is illuminated from an arbitrary direction, the polarization of the field measured in another arbitrary direction is a rotated version of the incident polarization. The rotation angle does not depend on the incident polarization.

We report on a new type of two-dimensional material system of sub-wavelength thickness, a plasmonic metasurface in atomic gas. Such plasmono-atomic metamaterial has unique properties underpinned by the interactions in the nearfield layer of the nanostructure.

We present an experimental demonstration of a new, monolithic dielectric resonator metasurface design that yields high quality-factor Fano resonances. Our approach utilizes perturbations of high-symmetry resonator geometries, such as cubes, to induce intra-resonator couplings between the otherwise orthogonal resonator modes.

<p> Here, we propose a novel mechanism to control the sign of the optical pressure on a material body. It is shown that the interference between a chiral light beam and its reflection on a mirror may allow pulling a chiral body with no optical traps towards the light source. Crucially, it is proven that this effect is independent of the specific location the body with the respect to the mirror and that the control of the incoming wave helicity may allow one to harness the sign of the optical force.</p>

Membrane projection lithography is used to create 3-dimensional unit cells in a silicon matrix decorated with metallic inclusions. The structures show pronounced resonances in the 4-16 micrometer wavelength range and demonstrate direct coupling to the magnetic field of a normally incident TEM wave, behavior only possible for vertically oriented resonators.

We show that by considering field transformation on two dimensional wave propagation, a real-space gauge field for photon can be identified as tilted anisotropy with realization using reciprocal and anisotropic metamaterials. It shifts the centers instead of changing sizes and shapes of the local dispersion surfaces to control light propagation. With a nontrivial gauge field and its associated pseudo-magnetic field, we show that optical spin-Hall effect and edge state for photon can be achieved with anisotropic metamaterials.