On multiple surface-plasmon-polariton waves guided by the interface of a metal film and a rugate filter in the Kretschmann configuration

The excitation of multiple surface-plasmon-polariton (SPP) waves—of different linear polarization states, phase speeds and spatial profiles—guided by the interface of a metal film and a rugate filter in the Kretschmann configuration was investigated. A plane wave of either of the two linear polarization states was made incident on the metal-capped rugate filter of finite thickness and the absorptances were calculated using a stable algorithm. The excitation of SPP waves was inferred by the presence of those peaks in the absorptance curves that were independent of the thickness of the rugate filter. The absorptance peaks representing the excitation of s-polarized SPP waves are narrower than those representing p-polarized SPP waves. For efficient excitation of multiple SPP waves, the metal film's thickness should be close to the penetration depth of the metal. The solution of a canonical boundary-value problem of SPP-wave propagation guided by a metal film, with a semi-infinite homogeneous dielectric material on one side and a semi-infinite rugate filter on the other side, reinforced the results obtained for the Kretschmann configuration. The thin metal film in the Kretschmann configuration may lead to coupling of its two interfaces.     

Surface electromagnetic waves on magnetic media

We assume complex magnetic and dielectric properties of two adjacent, isotropic, semi-infinite media and examine surface electromagnetic waves (SEW) at their plane interface. The dispersion curves and non-radiative conditions are derived and compared with other results. Comments are made about which materials will allow surface electromagnetic waves. The importances of the dielectric constants of the sample and the overlayer materials are emphasized with an example, Si and NiO.     

The surface plasmon polariton dispersion relations in a nonlinear-metal-nonlinear dielectric structure of arbitrary nonlinearity

The analytic surface plasmon polaritons(SPPs) dispersion relation is studied in a system consisting of a thin metallic film bounded by two sides media of nonlinear dielectric of arbitrary nonlinearity is studied by applying a generalised first integral approach.We consider both asymmetric and symmetric structures.Especially,in the symmetric system,two possible modes can exist:the odd mode and the even mode.The dispersion relations of the two modes are obtained.Due to the nonlinear dielectric,the magnitude of the electric field at the interface appears and alters the dispersion relations.The changes in SPPs dispersion relations depending on film thicknesses and nonlinearity are studied.     

Measurement of the dielectric constant of thin films by terahertz time-domain spectroscopic ellipsometry

We present a reflection-type terahertz time-domain spectroscopic ellipsometry (THz-TDSE) technique for measuring the complex dielectric constants of thin-film materials without replacement of the sample. THz-TDSE provides complex dielectric constants from the ratio of the complex amplitude reflection coefficients between p- and s-polarized THz waves. The measured dielectric constants of doped GaAs thin films show good agreement with predictions of the Drude model, even though the film thickness is of the order of a tenth of the penetration depth of the THz waves. In addition, we demonstrate the measurements of soft-phonon dispersion in SrTiO(3) thin films deposited on a Pt layer. The obtained dielectric constants agree well with the predictions of a generalized harmonic oscillator model.     

Nonlinear waves guided by a dielectric slab

We consider dispersion relations and field structure of TE-polarized guided waves travelling along an asymmetric dielectric slab surrounded by two different nonlinear media. For a given configuration there are four types of guided waves. Three of this four types possess at least one field maximum outside the slab region and have no counterpart in linear waveguide optics. The solutions of the dispersion relations depend now on an additional parameter making them more flexible with respect to the linear limit.     

Dispersion relations of hybrid waves in dielectric media

The dispersion relations of hybrid waves—polaritons, scalar bosons (hiddennons) and pseudoscalar bosons (axinons)—in one-dimensional dielectric media are derived with allowance for the resonant interaction between mechanical excitations of crystal lattices and elementary excitations of vacuum. It is shown that in the range of small wave vectors hybrid quasi-particles are formed in dielectric media: polaritons, hiddennons and axinons. For sodium nitrite crystal, dispersion relations of such hybrid quasiparticles are calculated near the center of the Brillouin zone. The resulting dispersion relations of hybrid quasi-particles provide conditions that allow observation of conversion of vacuum photon-like particles into hybrid quasi-particles in dielectrics, and also of parametric light scattering accompanied by the generation of hybrid quasi-particles.     

Resonant reflectance dips induced by coupled surface plasmon polaritons in thin metal-film/dielectric superlattices

The optical reflectance of metal films changes dramatically as the film thickness becomes thinner than the electron mean free path. We have developed a transfermatrix formalism for deducing the dispersion relations of the electromagnetic waves in infinite and semi-infinite metal-dielectric superlattices by taking into account the presence of the size effect and coupled plasmon waves. This work shows that the resonance frequency occurring at the reflecting dip increases while the bandwidth decreases as the thickness of the dielectric films increases. Reducing the values of p and q shifts the resonance frequency upward and yields multiple numbers of minimum reflectivity.     

Shear-horizontal waves in a rotated Y-cut quartz plate in contact with a viscous fluid

We study shear-horizontal (SH) waves in a crystal plate of rotated Y-cut quartz in contact with a semi-infinite viscous fluid. The crystal plate and the fluid are governed by the equations of anisotropic elasticity and the theory of Newtonian fluids. A transcendental equation that determines the dispersion relations of the waves is obtained. Approximate analytical solutions to the equation are presented for the case of low viscosity fluids and the case of long waves whose wavelength is much larger than the plate thickness. The effects of the fluid viscosity and density on the dispersion relations of the waves are examined. The results obtained are fundamental and useful to the understanding and design of acoustic wave fluid sensors for measuring fluid viscosity or density.     

非线性介质光波导中的传输功率和光学双稳态

本文对结构为非线性包层/线性芯层/非线性衬底的非线性介质光波导的传输特性进行了深入的分析,给出了模场分布函数,色散关系和传输功率的一组形式统一的公式,并对其传输功率的光学双稳态特性进行了讨论.     

On the theory of TE-polarized waves guided by a nonlinear three-layer structure

TE-polarized electromagnetic waves guided by a three-layer structure consisting of a film surrounded by semi-infinite media (all media are characterized by a Kerrlike dielectric function) are investigated by expressing the solution of the field equations in terms of Weierstrass' elliptic functions. Evaluation leads to a universal dispersion relation and its solutions and a universal expression for the power flow. Numerical results are presented for the effective wave number as a function of the intensity of the electric field at the lower surface of the nonlinear film, for various profiles of the field intensity, and for the power flow as a function of the effective wave number.     

三层非线性平面光波导TM波的精确色散关系

对于介质薄膜波导的一边或两边复盖有介电常数与光强成正比的非线性介质的三种不同结构，本文导出了三层非线性平面光波导ＴＭ波的精确色散关系。对称三层非线性平面光波导的数值计算实例与有限元法的结果完全一致。     

Nonexponentially Decaying Electromagnetic Waves Localized at the Boundary of Anisotropic Metal–Dielectric Structures

The possibility of the existence of a special class of surface electromagnetic waves with amplitude decreasing nonexponentially as they pass into an anisotropic metal–dielectric structure that borders the isotropic dielectric has been shown. The dispersion equation describing the propagation of such special surface waves has been obtained, and their attenuation coefficients and formula for electric and magnetic fields in contacting media have also been found. The expressions for the longitudinal and transverse components of the Poynting vector and volume density of electric and magnetic energy of special surface waves have been obtained. Numerical calculations for the layered metal–dielectric nanostructure that is described by a uniaxial tensor of effective dielectric permeability have been carried out Decaying.     

Controlled switching of surface waves in 1D photonic crystals by a thin nonlinear cap layer

In this paper, we investigate the electromagnetic surface waves localized at the interface of the homogeneous dielectric medium and a semi-infinite one-dimensional photonic crystal (1D PC), theoretically. The semi-infinite 1D PC is made of alternative layers of left-handed (LH) and right-handed (RH) materials in the presence of a thin nonlinear cap layer. We consider magnetic permeability and electric permittivity of LH layers being dispersive and non-dispersive. We used an analytical direct matching procedure within the Kronig-Penny model to analyze the dispersion behavior of surface waves with controllable localization. It is shown that the thin nonlinear cap layer acts as a tool to change the backward surface waves to forward ones and vice versa and it plays an important role on the localization of them. Also we show that when the LH layers are chosen dispersive, negative dispersion of surface waves are obtained in a wide range of radiation angle and frequency, and we propose an approach to calculate the applied electric field intensity that leads to switching of surface waves from backward to forward and creating a surface mode with maximum localization.     

Transverse or off-axis localization of electromagnetic waves in random one- and two-dimensional dielectric systems which are periodic on average

We study the transverse or off-axis localization of electromagnetic waves for several different random dielectric systems which are periodic on average. Unlike previous scalar wave treatments of transverse localization, in the present work we present results based on a full vector treatment of the electromagnetic fields based on Maxwell's equations. In a first system, we consider a random semi-infinite array of slabs with plane waves or finite beams of electromagnetic waves obliquely incident on the slab surfaces. The localization of the fields in a region near the surface of illumination is studied as a function of the oblique angle of incidence. In a second system, an array of semi-infinite slabs with random thickness is considered with an incident finite beam of electromagnetic waves initially directed parallel to the slab surfaces. The spreading of the beam width is computed as it propagates through the array of semi-infinite slabs. In a final system, we consider a semi-infinite array of random dielectric rods (2D system) with obliquely incident plane waves. The localization length of the plane-wave fields is computed as a function of the oblique angle of incidence and as a function of the strength of the disorder of the dielectric medium. All the random media we consider, when averaged over their randomness, are periodic on average. The above systems are studied for both p- and s-polarizations of incident electromagnetic waves, and the difference in the transverse localization of the electromagnetic field for these two polarizations is determined.     

Surface and Interface Optical-Phonon Modesin a Finite Four-Layer Heterostructure of Polar Crystals

The dispersion relation and eigen vector for the surface and interface optical-phonon modes in a finite four-layer heterostructure of polar crystals have been derived by using the dielectric con tinu um model. Moreover, as practical examples, the dispersion relations for some interesting structures such as finite and semi-infinite step quantum wells and a semi-infinite single quantum well are given for the first time.     

Analysis of the dispersion relations of nonlinear slab-guided waves

The dispersion relations of TE-polarized nonlinear guided waves (NGW) were investigated in detail. These waves travel along a dielectric slab embedded between two different nonlinear media. A simple relation between the effective nonlinear dielectric constants was established. All dispersion curves exhibit a particular transition point, where one evanescent field maximum changes from a virtual into a real one, and vice versa. Depending on the type of the remaining invariant evanescent field maximum, all NGW's split into two families. The lowest-order membres of every family play a particular role. The power flux supported by a NGW is derived, too.Preliminary results were presented at the XVI^th European Congress of Molecular Spectroscopy, Sofia, Bulgaria (1983)     

Surface electromagnetic waves at a superfluid liquid—normal metal interface

Surface electromagnetic waves, which can propagate along the plane interface between a superfluid liquid and a normal metal, are investigated. The dispersion relations for surface waves with different polarizations of the optical anisotropy of the superfluid liquid are obtained and their possible frequency ranges are determined. It is shown that anisotropic optical contribution to the dielectric constant of the superfluid liquid can be determined from experiments on excitation of surface electromagnetic waves.     

Quantum Theory of Surface Polaritons in Semi-Infinite Dielectric Systems

The interaction system of a semi-infinite diatomic dielectric and the electromagnetic field propagating parallelly to the surface is studied. The long-wave optical phonon modes of the semi-infinite dielectric are calculated including the electronic polarizability by a quantum-mechanical theory. Retardation effects are neglected. A quantum field theory method of surface polaritons is developed to calculate the operator describing the interaction between a photon and the phonon polarization fields of the semi-infinite crystal, with explicit inclusion of surface effects. The dispersion relations of the surface phonon-polaritons are derived and discussed. The results are in good agreement with those obtained by the conventional, macroscopic dielectric theory of surface polaritons and experimental ATR (attenuated total reflection) spectra. The dispersion cuwes of polariton leaking modes caused by the interaction between bulk TO mode with surface effect and photons are presented in a graphical form. The k_||-dependence of the electric field strength in each polariton branch is calculated and presented also in a graphical form. We also research the spatial dependence of the field strength in each polariton branch. It is found that these properties are influenced and modulated by the surface phonons because of the interaction between photons and the surface phonon modes of the semi-infinite dielectric system. Hence the divergent nature (diffraction effect) of light propagating along the fib& and waveguides is restrained. We present a method how to use the boundary conditions in the quantum theory, which will be discussed in detail.     

Reconstruction of dielectric permittivity profile of a plate with strong frequency dispersion

We demonstrate the possibility and propose the algorithm of unique reconstruction of the dielectric permittivity profile of a plate with a one-dimensional inhomogeneity (possibly, a plate with absorption), provided that the reflection and transmission coefficients of the plate for s-polarized plane waves are known in a certain range of incidence angles.     

Van der Waals interaction between a molecule and a metal surface: Effect of spatial dispersion

In this paper the effect of spatial dispersion on the dielectric response of a semi-infinite metal is investigated in the hydrodynamic approximation, and the result is used to evaluate the van der Waals force between a molecule and a metal surface. It is shown that corrections to the image potential result arising out of spatial dispersion can be evaluated systematically.