Illia V. Fedorin

Dispersion regions overlapping for bulk and surface polaritons in a magnetic-semiconductor superlattice

Extraordinary dispersion features of both bulk and surface polaritons in a finely stratified magnetic-semiconductor structure which is influenced by an external static magnetic field in the Voigt geometry are discussed in this Letter. It is shown that the conditions for total overlapping dispersion regions for the simultaneous existence of bulk and surface polaritons can be reached, providing a conscious choice for the constitutive parameters and material fractions for both magnetic and semiconductor subsystems.

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.

Electrodynamic properties of a thin-film periodic structure in an external magnetic field

Reflection and transmission of light by a bounded periodically layered structure formed by periodically repeated dielectric and semiconductor layers in a magnetic field are studied. The period of the structure is assumed to be much shorter than the wavelength. The magnetic field vector is parallel to the layer plane, and the wave propagation direction is perpendicular to the magnetic field. Passage to the limit of the thin-layer structure is performed. It is shown that the structure in this case is a biaxial crystal. The properties of the reflection and transmission coefficients are studied.

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.

Surface Electromagnetic Waves in Finite Semiconductor-Dielectric Periodic Structure in an External Magnetic Field

The speciflc features of TM-polarized surface electromag- netic waves in a flnite structure fabricated by a periodic alternating semiconductor and dielectric layers are investigated. Dispersion char- acteristics of eigenwaves are analyzed numerically and analytically. The complex Poynting energy ∞ux and the surface waves distribution are calculated. The in∞uence of geometrical and physical parameters of the structure on the properties of surface waves is studied.

Dispersion peculiarities of hybrid modes in a circular waveguide filled by a composite gyroelectromagnetic medium

Extraordinary dispersion features of a circular waveguide filled by a longitudinally magnetized composite gyroelectromagnetic medium are studied. The composite medium is considered to be constructed by juxtaposition together of magnetic and semiconductor layers providing all characteristic dimensions of the resulting multilayered system are much smaller than the wavelength in the corresponding part of the composite medium. The waveguide dispersion equation and its eigenmodes are derived. The mode classification is made in a standard manner so that the guided modes are sorted into a class of hybrid HE and EH waves in terms of their unique dispersion characteristics. The numerical results are obtained in the band near the frequencies of corresponding resonances in constitutive materials of the composite medium, and they show that the modes behaviors become to be quite diverse due to manifestation of a strong combined geometrical and material dispersion related to the waveguide parameters and gyroelectromagnetic filling, respectively.

The phenomenon of conical refraction in a thin-layer periodic semiconductor-dielectric structure in a magnetic field

The propagation of electromagnetic waves along the optical axes of a thin-layer periodic semiconductor-dielectric structure in an external magnetic field (i.e., under conditions of external and internal conical refraction) has been investigated. It is shown that the conditions for conical refraction can be implemented in certain regions by changing the external magnetic field, wave frequency, and thickness of the layers forming the structure. By varying the above-mentioned characteristics, one can efficiently control the conical refraction parameters; in particular, the opening angles of the cone of internal and external conical refraction and the inclination of the optical axes with respect to the periodicity axis can be varied in a wide range. The results of this study may be useful for designing millimeter-wave, submillimeter-wave, and IR devices.

Bi-hyperbolic isofrequency surface in a magnetic-semiconductor superlattice

The topology of isofrequency surfaces of a magnetic-semiconductor superlattice influenced by an external static magnetic field is studied. In particular, in the given structure, topology transitions from standard closed forms of spheres and ellipsoids to open ones of Type I and Type II hyperboloids as well as bi-hyperboloids were revealed and analyzed. In the latter case, it is found out that a complex of an ellipsoid and bi-hyperboloid in isofrequency surfaces appears as a simultaneous effect of both the ratio between magnetic and semiconductor filling factors and magnetic field influence. It is proposed to consider the obtained bi-hyperbolic isofrequency surface as a new topology class of the wave dispersion.

Modal Phenomena of Surface and Bulk Polaritons in Magnetic- Semiconductor Superlattices

We discuss peculiarities of bulk and surface polaritons propagating in a composite magnetic-semiconductor superlattice influenced by an external static magnetic field. Three particular configurations of magnetization, namely the Voigt, polar and Faraday geometries are considered. In the long-wavelength limit, involving the effective medium theory, the proposed superlattice is described as an anisotropic uniform medium defined by the tensors of effective permittivity and effective permeability. The study is carried out in the frequency band where the characteristic resonant frequencies of the underlying constitutive magnetic and semiconductor materials of the superlattice are different but closely spaced. The effects of mode crossing and anti-crossing in dispersion characteristics of both bulk and surface polaritons are revealed and explained with an assistance of the concept of Morse critical points from the catastrophe theory.

Adaptive control of hybrid modes in a longitudinally magnetized gyroelectromagnetic circular waveguide

In this report, dispersion properties of a circular waveguide filled by a composite gyroelectromagnetic structure, which consists of alternating ferrite and semiconductor layers are studied. The system is supposed to be longitudinally magnetized, i.e. the static external magnetic field is applied along the axis of the guide, perpendicularly to the layers of the structure. The system is considered to be in the subwavelength regime, and the relative effective permittivity and permeability of the waveguide filling are introduced. The waveguide dispersion equation and its eigenmodes are derived. Unique dispersion characteristics of supported hybrid modes are investigated. It is shown that simultaneous presence of gyromagnetic and gyroelectric eifects in the waveguide system can gain a substantial control under the dispersion characteristics and field distributions of the supported modes.