Enhanced transmission by a grating composed of left-handed materials

We present a detailed theoretical analysis about the influence of surface polaritons on the transmission properties of electromagnetic waves at the periodically corrugated interface between the vacuum and left-handed material by using nonlinear boundary condition approach. The principle behind this approach is to match the wave fields across the grating interface by using a set of linear wave equation with nonlinear boundary conditions. The resonant transmission of the incident electromagnetic radiation in this structure is feasible within a certain frequency band, where there is a range of frequency over which both the electric permittivity and the magnetic permeability are simultaneously negative. The enhanced transmission is attributed to the coupling of the incident electromagnetic wave with the excited surface polaritons on grating interface. Finally, we present the numerical results illustrating the effect of the structural parameters and angle of incidence on the transmission spectra of a TM polarized electromagnetic wave.     

Propagation properties of guided surface polaritons — a new class of electromagnetic waves

The propagation properties and field structures of a new class of electromagnetic surface excitations, the so-called guided surface polaritons, are investigated. These waves exhibit features of both film-guided modes and surface polaritons. The conditions of their existence dependent on the optical constants are discussed. The three-dimensional waveguide problem is treated by a rigorous mathematical formalism.     

Pseudosurface dispersion polaritons and their resonance excitation

The conditions for the transformation of surface polaritons (surface electromagnetic waves) into pseudosurface polaritons under the influence of perturbations are investigated. The transformation occurs because of the appearance of a weak energy loss flow typical of pseudosurface polaritons, which carries energy away from the surface of the solid. The dispersion polaritons existing at negative values of the dielectric constant are considered. The domain of existence of the pseudosurface polaritons is studied; their main characteristics and the parameters of the resonance excitation of these polaritons by a pumping wave are investigated.     

Dispersion and instability of electromagnetic waves in layered periodic semiconductor structures

The effect of carrier drift on the dispersive properties and instability of electromagnetic waves and plasma polaritons in infinite layered periodic semiconductors are considered. It is assumed that in similar semiconductor layers, carriers drift parallel to the interfaces. Drift waves are shown to have a specific band structure of the spectrum. The dispersive properties of collective plasma polaritons under drift are considered, the instability of the polaritons and drift waves is studied, and the instability increments are determined.     

Applicability conditions for the dipole approximation in the problems of scattering of surface plasmon polaritons

Using the method of the tensor Green’s function of the wave equation, the conditions have been determined under which the dipole approximation is sufficient in the problem of the scattering of surface optical electromagnetic waves (surface plasmon polaritons) on a small spherical particle. The independence of the electric field inside the scatterer of the spatial coordinates is used as the main requirement of the dipole approximation. Conditions are obtained in the form of inequalities involving the wavenumber, the material parameters of the system, and the size of the scatterer and its position with respect to the surface on which plasmon polaritons are excited.     

左手系材料界面上的非线性TE电磁波

针对电磁波在非线性左手系材料中的传播性质, 分别研究了左、右手系材料界面以及两左手系材料界面上非线性TE表面波的传播行为讨论了导波的频率特性、色散关系以及群速度随频率的变化规律分析表明,两种界面上的非线性TE表面波均存在频率通带和禁带,且带宽是传播功率的函数揭示了在一定条件下,左、右手系材料界面上既可以支持正向传播的非线性TE表面波,也可以支持反向传播的非线性TE表面波;两左手系材料界面上表面波的传播性质因材料参量的变化差异较大,一定参量条件下,该界面上仅支持反向传播的非线性TE表面波.     

External electric field effects in the resonant propagation of a TM- or TE-Type wave through an orthoferrite plate under the conditions of a Morin-type phase transition

Questions associated with the propagation of a TM- or TE-type bulk wave through a half-wave plate and arising due to the influence of crossed constant magnetic and electric fields are studied through the example of orthoferrite under the conditions of a Morin-type phase transition. The correspondence of resonant propagation conditions to both the spectrum of outgoing bulk magnetic layer polaritons and the spectrum of electromagnetic waves of a plate with extreme surface impedance is demonstrated.     

Spectra of magnetoplasma polaritons in a semiconductor layer on a metallic substrate

The dispersion properties of volume and surface magnetoplasma polaritons in a three-layer metal-semiconductor-insulator structure are studied. It is predicted that surface magnetoplasma polaritons propagating on the two boundaries of the semiconductor layer interact resonantly. It is shown that for a certain direction of propagation the dispersion curves of surface and volume magnetoplasma polaritons contain sections with negative dispersion. Nonreciprocal propagation of volume magnetoplasma polaritons has been observed. Losses in the semiconductor layer split the starting spectral lines into dispersion curves of two types, corresponding to forward and backward waves.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 38–43, January, 1988.     

Surface polaritons in composite media with time dispersion of permittivity and permeability

The propagation of electromagnetic waves in a composite medium based on an array of conducting wires in a ferromagnetic nonconducting matrix is discussed. It is demonstrated that, in certain ranges of frequencies and wavelengths, the composite under investigation can possess properties inherent in a “left-handed” medium. The regions of the existence of bulk and surface localized electromagnetic waves are explored. Consideration is given to the dispersion of surface electromagnetic waves in thick layers of the composite.     

Transverse surface and slab modes in semiconductor superlattices

It is shown from the exact equations for transverse electromagnetic waves propagating in a superlattice that in the long-wavelength limit the superlattice has the optical properties of a conventional uniaxial medium. This result is used to derive the dispersion equations for polaritons at single and double interfaces between superlattices and ordinary media.     

Electromagnetic waves in uniaxial crystals with metallized boundaries: Mode conversion,pure reflections,and bulk polaritons

A theory is constructed for the reflection of plane electromagnetic waves in uniaxial crystals with a positive definite permittivity tensor and an arbitrarily oriented metallized boundary. The problem is solved both for general-position orientations corresponding to three-partial reflection and for special conditions allowing two-partial reflections: mode conversions when the incident and reflected waves belong to different sheets of the refraction surface and “pure” reflections when both waves belong to the same sheet. The space of pure reflections is shown to be formed by two types of optical-axis orientations: arbitrary directions in the plane of the crystal surface and in the plane of incidence. The configurations of the conversion surface for optically positive and negative crystals are investigated. A subspace of pure reflections that transform into one-partial bulk polaritons with the energy flux parallel to the surface at grazing incidence has been found. The domain of existence of such bulk eigenmodes is bounded by two “lines” of solutions. These are any directions along the boundary containing the optical axis for ordinary polaritons and the direction along the projection of the optical axis onto the surface at an arbitrary orientation of the axis with respect to the boundary for extraordinary polaritons.     

Cylindrical electromagnetic waves in a nonlinear nondispersive medium: Exact solutions of the Maxwell equations

The excitation and propagation of cylindrical electromagnetic waves in a nonlinear nondispersive medium are analyzed. It is assumed that the medium lacks a center of symmetry and that the dependence of the electric displacement on the electric field can be approximated by an exponential function. For this case, a method for integrating the system of the Maxwell equations is proposed. Exact solutions to a set of nonlinear electromagnetic field equations are obtained by this method. It is shown that nonlinear effects described by these solutions can become apparent under experimental conditions.     

Instability of polaritons driven by infrared laser light

In the present paper the nonlinear behavior of lattice vibrations driven by a coherent electromagnetic wave on the basis of Huang's equations is discussed. Under certain conditions formulated in the text these mixed electromagnetic lattice waves (polaritons) become unstable for some regions of the parameters of the incident laser light. Unstable motion of crystal lattices may be considered as a damage mechanism of the crystal structure.     

Surface electromagnetic waves at the interface between dissipative porous nanocomposite and hypercrystal under different temperatures

In the current paper the properties of surface plasmon polaritons as well as hybrid polarized surface electromagnetic waves at the plane interface of a porous semiconductor nanomaterial and a hypercrystal are studied theoretically and numerically. The nanomaterial, as well as the hypercrystal, is made of n-type doped indium antimonide (n-InSb) semiconductor layers. The losses which inherent to the semiconductor materials are taken into account. To describe the properties of the constituent semiconductor layers the approximate analytical temperature models for concentration and mobility of conduction electrons are applied. This allows to consider the effect of electron scattering on the properties of supported electromagnetic modes in the wide frequency range. The contacting materials are considered in the subwavelength approximation when it is possible to introduce the effective permittivity components. It is shown that taking into account dissipation processes in the semiconductor constituent layers result in the appearance of additional surface modes branches, changes in the surface waves penetration depth, frequency and angular existence domains.     

Total absorption of an electromagnetic wave by an overdense plasma

We show both theoretically and experimentally that an electromagnetic wave can be totally absorbed by an overdense plasma when a subwavelength diffraction grating is placed in front of the plasma surface. The absorption is due to dissipation of surface plasma waves (plasmons polaritons) that have been resonantly excited by the evanescent component of the diffracted electromagnetic wave. The developed theoretical model allows one to determine the conditions for the total absorption.     

Modelling of nonlinear surface gravity waves under shallow-water conditions with account of dispersion

The modelling of nonlinear surface gravity waves under shallow-water conditions with account of dispersion is described in this study. On the basis of the analytic expressions obtained for the horizontal velocity of medium particles, the profile evolution of nonlinear surface gravity waves during its propagation under shallow-water conditions is described. The profiles of surface gravity waves during their propagation in the bay with account of dispersion are given.     

含单负材料三明治结构的电磁隧穿特性

在理论分析的基础上,结合实验研究了单负材料/正折射率材料(或单负材料)/单负材料三明治结构的电磁隧穿性质.这种结构的电磁隧穿来源于入射平面波与结构的表面或体极化激元的耦合,从理论上讨论并计算了正入射情况下这种结构中的极化激元的色散关系.发现:由单负材料作为边界而正折射率材料为中间层的三明治结构具有体极化激元,这种极化激元的共振频率随着中间层厚度的增加向低频移动;由不同性质的单负材料构成的三明治结构具有两条色散曲线,这两条色散曲线随着中间层厚度的增加而简并.随后基于L-C传输线技 关键词： 单负材料 极化激元 隧穿 L-C传输线')" href="#">L-C传输线     

Perturbation theory results for the diffuse scattering of light from two-dimensional randomly rough metal surfaces

Using the unitarity and reciprocity preserving formulation of Brown et al a perturbation treatment, correct to fourth order in the surface profile function, is given for the scattering of electromagnetic waves from a weakly rough, two-dimensional, random metal surface. In this formulation the boundary conditions on the electromagnetic fields are satisfied using the extinction theorem in conjunction with the Rayleigh hypothesis and the vector equivalent of the Kirchhoff integral. The theory is applied to, and results are presented for, several different types of rough surfaces which are characterized by power spectra that are extensions to two-dimensional random surfaces of the power spectrum of some one-dimensional random surfaces recently fabricated by West and O'Donnell. These surfaces, which can be realized experimentally, favor coherent, interferent, multiple scattering of electromagnetic waves via surface plasmon polaritons in intermediate states, and clearly exhibit enhanced backscattering caused by the surface plasmon polariton mechanism. Theoretical results are presented for silver surfaces at optical wavelengths.     

Excitation of terahertz surface polaritons in a cylindrical waveguide by femtosecond laser pulses

Generation of terahertz surface polaritons in homogeneous round cross-section plasma waveguides upon nonlinear optical rectification of femtosecond laser pulses is analyzed theoretically. It is assumed that nonlinear polarization inducing a surface electromagnetic wave is formed at the waveguide boundary in a thin layer of the nonlinear dielectric that surrounds the waveguide. The efficiency of the femtosecond radiation conversion into surface polaritons is studied as a function of the waveguide radius and duration of the exciting laser pulse.