Optical method for measuring the coupling constant of surface acoustic waves

The coupling constant of common or thin-layered-piezoelectric interdigital transducers for surface acoustic waves up to the highest frequencies can be determined in an optical way with reproducibility better than 3%. Being a nondestructive and noncontact method one can apply it in the technological process for fabricating uniform piezoelectric layered transducers.     

Guided electromagnetic waves at the interface between a dielectric and a topological insulator

Surface electromagnetic waves that propagate within the interface between a conventional dielectric or a metamaterial and a topological insulator with an undamped surface electric current are considered. Dispersion relations are given for guided waves that are surface waves polarized differently on either side of the media interface and create a coupling state due to the magnetoelectric effect.     

On the properties of electromagnetic waves propagating inside moving dielectric media

The properties of electromagnetic waves propagating inside isotropic or uniaxial dielectric media moving in an arbitrary direction are analysed. The scalar products of electromagnetic field vectors inside these moving media are investigated in the kEB system from Maxwell's equations and Lorentz-covariant constitutive relations. Several important equations are derived. They are useful in discussing problems such as the energy density and radiation pressure, which are of interest in theoretical studies and many application subjects.     

Reflection and transmission of plane waves at the interface between anisotropic random discrete media

The Maxwell equations are solved for a random discrete medium using the single-scattering approximation and the condition of immersion in a maximally packed medium. The reflection and transmission factors of plane waves at the interface between vacuum and a random discrete anisotropic medium are determined. The calculated and experimental results on reflection and transmission of plane waves near the edge of a forest as an example of natural anisotropy of a random discrete medium are compared.     

The dielectric constant of PbTe at 4.2 K and\tilde v=84.15 cm-1, 96.97cm−1, 103.60cm−1

The dielectric constant of a PbTe epitaxial layer has been measured by surface wave spectroscopy using an optically pumped far-infrared laser and the technique of attenuated total reflection.     

Phase function of long helical particles at normal and oblique incidence

This paper studies characteristics of the electro-magnetic wave scattering by a long helical particle in cases of oblique incidence with different polarizations. The dependence of the resonant peaks and the phase function on the incidence angle is analyzed for different values of helix parameters. The analysis is based on the model developed by the authors and presented in previous publications.     

Simulation and analysis of interaction between oblique incidence electromagnetic wave and plasma slab

Numerical simulation of interaction between plasma slab and electromagnetic wave which has different incident frequency and incident angle is discussed in this paper. Some parameters contain reflection coefficient, transmission coefficient, reflectance, transmittance and phase are calculated by transfer matrix method. The relation of these parameters with incident frequency and incident angle is analyzed. The results show that the incident angle has low influence on the parameters when the angle varies from 0° to 30° and from 70° to 90°, but it has high influence on the parameters when it changes from 30° to 70°. These rules have certain directive significance to the research of interaction between oblique incidence electromagnetic wave and plasma slab and to the design of plasma layer.     

双传声器法测量斜入射吸声系数研究

本文从理论和实验两方面研究了双传声器法测量斜入射吸声系数时,双传声器间距,双传声器离材料表面距离,材料面积大小等因素对测量结果的影响。     

Reflected and transmitted powers of arbitrarily polarized plane waves at interface between chiral and achiral media

A study has been made on the reflected and transmitted powers generated when an arbitrarily polarized plane wave impinges at a planar interface separating an isotropic achiral medium(IAM) and an isotropic chiral medium(ICM). It follows that the theoretical formulas are derived for the normalized reflection and transmission powers from an IAM–ICM interface for an arbitrary polarized incident wave, and those at an ICM–IAM interface for right-hand circularly polarized(RCP) or left-hand circularly polarized(LCP) incident wave are also obtained. The behavior of the reflected and transmitted waves in different cases is studied, and the dependence of the reflection/transmission of the incident wave on the incident angle and the parameters of the media is investigated in detail. Our numerical results show that high transmission is exhibited under the impedance matching condition and the incident wave can be split into two waves of the same circular polarization state in the case of the ICM–IAM interface, which indicates that circular polarizing beam splitter is achieved.     

The velocity distribution of sputtered Zr atoms for irradiation at normal and oblique angle of incidence

Laser-induced fluorescence by means of a cw dye laser has been used for investigating the velocity distribution of sputtered Zr atoms in the ground state. In order to evaluate the data the excitation probability of the atoms in the observation volume has been measured. The velocity distribution of Zr atoms for irradiation with Ar⁺-ions as well as light ions at normal and oblique angle (70°) of incidence is presented.     

Extinction theorem and propagation of electromagnetic waves between two anisotropic materials

We systematically investigate the reflection and refraction of an electromagnetic wave between two semi-infinite anisotropic magnetoelectric materials. Using the integral formulation of Hertz vectors and the principle of superposition, we generalize the extinction theorem and derive the propagation characteristics of wave. Applying the results obtained, we find a general origin of Brewster effect. We also show that, through choosing appropriate material parameters, oblique or omnidirectional total transmission can occur to TE and TM waves. Compared to the traditional method, the method used here discloses the underlying mechanism of wave propagation between two arbitrary anisotropic materials and can be applied to other problems of propagation.     

Calculation of the near fields for the scattering of electromagnetic waves by multiple infinite cylinders at perpendicular incidence

The near field solution for the scattering of a plane monochromatic electromagnetic wave by an ensemble of parallel infinite dielectric cylinders at perpendicular incidence is presented in this paper. The solution is given for the calculation of the electric and magnetic near fields and the Poynting vector. A MATLAB program has been developed to solve the near field formulas which is introduced and validated. The near to far field transition as well as formation and transport of photonic nanojets have been calculated for multiple cylinder scattering.     

Angular control of acoustic waves oblique incidence by phononic crystals based on Dirac cones at the Brillouin zone boundary

This study investigated the angular control of incident acoustic waves for total transmission and reversed reflection using phononic crystals (PnCs). The Dirac point appears at the Brillouin zone boundary. The position of the Dirac point regularly changes with the length–width ratio of rubber rods, which makes the transmission angle adjustable. These structures could be applied to an acoustical 0 or π phase modulator by adjusting the number of layers of PnCs (even or odd). The angular control in the reflection domain can be achieved by adding a meta-surface at the boundary of the PnC.     

On the orthogonality of the phase velocity and its feasibility for plane waves

Phase and group velocities of plane waves may have different directions in a linear and homogeneous medium. This difference may lead to interesting situations such as the phase reversal propagation and the orthogonal phase velocity. Although the former has been analyzed in depth and it has found many applications, the latter has been left as a hypothesis. Actually, due to our best knowledge there is no evidence of such media where the phase velocity is orthogonal to the group velocity. In this paper we discuss this situation thoroughly. We show that a plane wave with orthogonal phase velocity cannot possess linear momentum. Moreover, we show that a plane wave without the linear momentum cannot propagate at all, so the orthogonality of the phase velocity does not take place in reality for electromagnetic plane waves.