Vladimir R. Tuz

Optical bistability involving planar metamaterials with broken structural symmetry

We report on a bistable light transmission through a planar metamaterial consisted of a metal pattern of weakly asymmetric elements placed on a nonlinear substrate which enables sharp resonance response by excitation of a trapped mode. A feedback required for bistability is provided by the coupling between strong trapped mode resonance antiphased currents exited on the metal elements and an intensity of inner field in the nonlinear substrate.

Polarization switching and nonreciprocity in symmetric and asymmetric magnetophotonic multilayers with nonlinear defect

A one-dimensional magnetophotonic crystal with a nonlinear defect placed either symmetrically or asymmetrically inside the structure is considered. Simultaneous effects of time-reversal nonreciprocity and nonlinear spatial asymmetry in the structure are studied. Bistable response is demonstrated in a such system, accompanied by abrupt polarization switching between two circular or elliptical polarizations for transmitted and reflected waves. The effect is explained in terms of field localization at defect-mode spectral resonances and can be used in the design of thin-film optical isolators and polarization transformation devices.

Optical properties of a quasi-periodic generalized Fibonacci structure of chiral and material layers

The reflection and transmission coefficients of the perpendicular and parallel polarization plane electromagnetic waves of a finite quasi-periodic Fibonacci sequence of chiral and convenient isotropic magnetodielectric layers are obtained using the 2×2-block-representation transfer-matrix formulation. A correlation has been established between geometrical and spectral properties of the structure under consideration. Numerical simulations are carried out for different structures to reveal the dependence of the reflection and transmission coefficients on the frequency, chirality parameter, and the angle of wave incidence.

Depolarization properties of a periodic sequence of chiral and material layers

We consider the electromagnetic field due to the reflection and transmission of a plane wave by a bounded periodic structure containing chiral layers. The problem is solved using the 2x2-block-representation transfer-matrix formulation. The frequency and angular dependences of the reflection and transmission coefficients are given. The boundaries of the passbands and stopbands are determined from the basic-element transfer-matrix eigenvalue analysis.

Gyrotropic-Nihility in Ferrite-Semiconductor Composite in Faraday Geometry

The reflection, transmission spectra and the polarization transformation of linearly polarized waves in the ferrite-semiconductor multilayer structure are considered. In the long-wavelength limit, the effective medium theory is applied to describe the studied structure as a uniaxial anisotropic homogeneous medium defined by the effective permittivity and effective permeability tensors. The investigations are carried out in the frequency band where the real parts of the diagonal elements of both the effective permittivity and permeability tensors are close to zero. In this frequency band the studied structure is referred to a gyrotropic-nihility medium. An enhancement of polarization rotation, impedance matching, backward propagation are revealed.

Polarization properties of symmetrical and asymmetrical nonreciprocal chiral photonic bandgap structure with defect

The polarization properties of perfectly periodical and defective one-dimensional photonic bandgap structures with nonreciprocal chiral (bi-isotropic) layers are studied. The method of solution is based on the 2×2 block-representation transfer-matrix formulation. Numerical simulations are carried out for different types of structures (symmetrical or asymmetrical) in order to reveal the dependence of the reflection and transmission coefficients on frequency, chirality, nonreciprocity parameters, and angle of wave incidence.

Enhancement of absorption bistability by trapping-light planar metamaterial

We propose to achieve a strong bistable response of a thin layer of a saturable absorption medium by involving a planar metamaterial specially designed to bear a high-Q trapped-mode resonance in the infrared region.

Coexistence of bulk and surface polaritons in a magnetic-semiconductor superlattice influenced by a transverse magnetic field

It is demonstrated that the effect of coexistence of bulk and surface polaritons within the same frequency band and the wavevector space can be achieved in a magnetic-semiconductor superlattice, providing a conscious choice of characteristic resonant frequencies and material fractions of the structures underlying components as well as geometry of the external static magnetic field. The study is based on the effective medium theory, which is involved to calculate dispersion characteristics of the long-wavelength electromagnetic modes of ordinary and extraordinary bulk polaritons, and hybrid surface polaritons with dominant longitudinal component of either magnetic (HE) or electric (EH) field derived via averaged expressions with respect to the effective constitutive parameters of the superlattice.

Crossing and anti-crossing effects of polaritons in a magnetic-semiconductor superlattice influenced by an external magnetic field

Abstract Crossing and anti-crossing effects in dispersion characteristics of both bulk and surface polaritons in a magnetic-semiconductor superlattice influenced by an external static magnetic field being in the Faraday geometry are discussed. The bulk polaritons are classified as eigenwaves with right-handed and left-handed elliptically polarized states, whereas the surface polaritons are considered as hybrid modes having a predominant effect of either magnetic or semiconductor subsystem, and distinctions in dispersion characteristics of such polaritons are revealed involving the concept of critical points.

Optical Bistability in a Grating with Slits Filled Nonlinear Media

An approximate self-consistent solution of the problem of plane electromagnetic wave difiraction on a thick grating of metallic bars with slits between the bars fllled a Kerr-type nonlinear dielectric is solved. The bistable operating regime of wave transmission through the grating is studied.