Mitigating Snell’s-Law Reflection and Transmission with Metasurfaces of Ordinary Dielectrics

Obtaining anomalous reflection and transmission (namely propagation along directions different from those predicted by Snell’s law) is investigated for plane waves impinging on a planar periodic metasurface composed of two dielectric layers. The associated boundary-value problem is treated by a rigorous entire-domain integral equation methodology. Optimizations with respect to the con- figuration’s parameters are performed which reveal that it is possible to obtain significantly enhanced anomalous transmission and reflection depending on the color of the incident light. The optimal parameter values correspond to metasurfaces which can be easily realizable by low-loss dielectric materials

Higher-order effects and ultra-short solitons in left-handed metamaterials

Starting from Maxwell's equations, we use the reductive perturbation method to derive a second-order and a third-order nonlinear Schroedinger equation, describing ultra-short solitons in nonlinear left-handed metamaterials. We find necessary conditions and derive exact bright and dark soliton solutions of these equations for the electric and magnetic field envelopes.Comment: 4 pages, 2 figures, Phys. Rev. E in pres

Giant enhancement of the controllable in-plane anisotropy of biased isotropic noncentrosymmetric materials with epsilon-negative multilayers

Giant in-plane anisotropy can be exhibited by a finitely thick periodic multilayer comprising bilayers of an isotropic noncentrosymmetric material and a non-dissipative isotropic medium of negative permittivity, when a dc electric field is applied in the thickness direction. Compared to a homogeneous layer of the noncentrosymmetric material with the same thickness as the periodic multilayer, the latter exhibits an effective in-plane anisotropy that can be three orders larger in magnitude. This enhancement gets more substantial at higher frequencies and is electrically controllable. The incorporation of dissipation reduces the enhancement of the effective in-plane anisotropy, which nevertheless remains significant. We expect the finitely thick periodic multilayer to be useful as a polarization transformer or a modulator in the terahertz regime fully controllable via external dc bia

Wide-angle absorption of visible light from simple bilayers

Color-selective absorption of light is a very significant operation used in numerous applications, from photonic sensing and switching to optical signal modulation and energy harnessing. We demonstrate angle-insensitive and polarization-independent absorption by thin bilayers comprising ordinary bulk media: dielectrics, semiconductors, and metals. Several highly efficient designs for each color of the visible spectrum are reported, and their internal fields’ distributions reveal the resonance mechanism of absorption. The proposed bilayer components are realizable, since various physical or chemical deposition methods can be used for their effective fabrication. The absorption process is found to exhibit endurance with respect to the longitudinal dimension of the planar structure, which means that the same designs could be successfully utilized in non-planar configurations composed of arbitrary shapes

Ultrashort pulses and short-pulse equations in (2+1)−(2+1)-dimensions

In this paper, we derive and study two versions of the short pulse equation (SPE) in $(2+1)-$dimensions. Using Maxwell's equations as a starting point, and suitable Kramers-Kronig formulas for the permittivity and permeability of the medium, which are relevant, e.g., to left-handed metamaterials and dielectric slab waveguides, we employ a multiple scales technique to obtain the relevant models. General properties of the resulting $(2+1)$-dimensional SPEs, including fundamental conservation laws, as well as the Lagrangian and Hamiltonian structure and numerical simulations for one- and two-dimensional initial data, are presented. Ultrashort 1D breathers appear to be fairly robust, while rather general two-dimensional localized initial conditions are transformed into quasi-one-dimensional dispersing waveforms

Source amplitudes for active exterior cloaking

The active cloak comprises a discrete set of multipole sources that destructively interfere with an incident time harmonic scalar wave to produce zero total field over a finite spatial region. For a given number of sources and their positions in two dimensions it is shown that the multipole amplitudes can be expressed as infinite sums of the coefficients of the incident wave decomposed into regular Bessel functions. The field generated by the active sources vanishes in the infinite region exterior to a set of circles defined by the relative positions of the sources. The results provide a direct solution to the inverse problem of determining the source amplitudes. They also define a broad class of non-radiating discrete sources.Comment: 21 pages, 17 figure

Vector solitons in nonlinear isotropic chiral metamaterials

Starting from the Maxwell equations, we used the reductive perturbation method to derive a system of two coupled nonlinear Schr\"{o}dinger (NLS) equations for the two Beltrami components of the electromagnetic field propagating along a fixed direction in an isotropic nonlinear chiral metamaterial. With single-resonance Lorentz models for the permittivity and permeability and a Condon model for the chirality parameter, in certain spectral regimes, one of the two Beltrami components exhibits a negative real refractive index when nonlinearity is ignored and the chirality parameter is sufficiently large.We found that, inside such a spectral regime, there may exist a subregime wherein the system of the NLS equations can be approximated by the Manakov system. Bright-bright, dark-dark, and dark-bright vector solitons can be formed in that spectral subregime.Comment: 14 pages, 2 figure

Achieving Anomalous Refraction with Metasurfaces Composed by Two Ordinary Dielectric Materials

The optimal parameters of a dielectric metasurface, composed of two alternating rectangular rods, are investigated so that it exhibits significant enhancement in the −1- diffracted order in the transmission region. An efficient integral-equation methodology is used for the numerical computations. Representative results of initial optimizations are presente

ON THE INTERIOR DIPOLE EXCITATION OF A LAYERED CHIRAL SCATTERER

A layered chiral scatterer is excited by a time harmonic spherical electromagnetic wave, generated by a dipole located in the interior of the scatterer. The investigation of such excitation problems is motivated by significant applications including for example radiation from antennas embedded in chiral media and from chiral in chiral composites as well as medical implantations inside the human body. Reciprocity and general radiation theorems are established, relating the Beltrami fields with the corresponding far field patterns. The theorems recover as special cases the respective known results for chiral and achiral media