Total reflection of light propagating from an isotropic medium to an anisotropic medium

We study the propagation of light from an isotropic medium to an anisotropic medium. It is shown that total reflection can occur only for propagation from a denser medium to a rarer medium; this result does not agree with that of Lin and Wu [Opt. Lett. 23, 22 (1998)].     

Total reflection of waves propagating from an isotropic medium to an anisotropic medium

We examine the value n(i)/n(eff)(theta(t)) , the ratio of the indices of refraction for waves transmitted from an isotropic medium to an anisotropic medium. It is found that total reflection can occur in the case of propagation from a rarer medium to a denser medium.     

Inverted (negative) refraction of an electromagnetic wave in an anisotropic medium

Through the example of a uniaxial crystal, it is shown that inverted (negative) refraction of an electromagnetic wave in an anisotropic medium (in contrast to an isotropic medium) may occur even when the spatial dispersion of the dielectric tensor is neglected.     

Reflection of electromagnetic plane waves in a long-wavelength approximation from a multilayer system of anisotropic transparent films on non-absorbing isotropic medium

The reflection of s- and p-polarised electromagnetic plane waves from an N-layer system of anisotropic dielectric films upon transparent homogeneous substrate is investigated in the long-wavelength approximation. The analytical expressions are obtained for the amplitude reflection (transmission) coefficients, reflectances (transmittances), and ellipsometric angles of an anisotropic multilayer thin-film system. All analytical results are in agreement with the numerical solution of the reflection problem for anisotropic stratified medium. The possibilities of using obtained expressions for resolving the inverse problem for ultrathin anisotropic films upon isotropic substrates are discussed.     

Total reflection of electromagnetic waves propagating from an isotropic medium to an indefinite metamaterial

The existence conditions for total reflection and the corresponding critical angle at the interface separating an isotropic medium and an indefinite metamaterial for TE- and TM-polarized electromagnetic waves are obtained. For different kinds of indefinite metamaterial, there appear different total reflection phenomena. Particularly, the anomalous total reflection in which the incident angle is smaller than the critical angle and the Brewster’s angle can be smaller than the critical angle can occur for anti-cutoff medium. Furthermore, the omnidirectional total reflection exists for the always cutoff medium and anti-cutoff medium. The total reflection depends on the thickness of indefinite metamaterial when the indefinite metamaterial is finite, and the photon tunneling phenomenon can occur when the thickness of indefinite metamaterial is smaller than wavelength.     

Babinet's principle in an anisotropic medium

The results of the theory of diffraction in an isotropic medium are used to derive relations between the vectors of electromagnetic fields produced by diffraction on complementary screens, for the case of two-dimensional diffraction in an electrically anisotropic medium.     

A two-step strategy for numerical simulation of radiative transfer with anisotropic scattering and reflection

This article presents a two-step procedure for the computation of radiative heat transfer with anisotropic scattering and reflection. It is based on a concept that the coincident processes of absorption and scattering/reflection can be separated factitiously. All medium elements and wall surfaces are supposed to be pure-absorbing when receiving incident radiation. Afterwards they emit the scattered/reflected radiations. The absorption of both the initial and the secondary radiations can be assessed by the direct exchange area. It is needed to repeat the processes for a few times until the radiations are substantially absorbed. For anisotropic scattering/reflection, a vector summation obtains the directional distribution of emissive power. The method is validated by several benchmark computations in terms of emissive power and heat transfer coefficients. It is shown that the method gives more accurate solution than the isotropic scaling for the heat transfer in anisotropically scattering media.     

光波p分量在单轴晶体表面反射和折射的相位特性

根据单轴晶体的双折射和双反射性质,通过数值计算研究了光轴在入射面内并与晶体界面成任意角时光波p分量在单轴晶体表面反射和折射的相位特性.结果表明,光轴取向对相位变化有较大影响,光从光疏各向同性介质射入单轴晶体时,光轴方向改变反射光p分量的相位突变点,但对折射光p分量相位无影响.光从光密各向同性介质射入单轴晶体未发生全反射时,光轴方向同时影响p分量反射光和折射光的相位突变|发生全反射后,光轴方向影响反射光p分量的相位变化曲线.从单轴晶体出射到光疏各向同性介质未发生全反射时,光轴方向改变反射光p分量的相位跃变规律,折射光p分量在光轴方向和晶面成小角度时在布儒斯特角附近发生相位突变|发生全反射后,反射光p分量的相位变化曲线随光轴方向的改变发生较大变化.     

Amplitudenverhältnisse bei der Reflexion und Brechung des Lichtes an der Grenzebene zwischen isotropen und anisotropen Medien

Relations for the Amplitudes in Case of Reflection and Refraction of Light at the Boundary Plane between Isotropic and Anisotropic Media Relations for the amplitudes of the electric fields of plane monochromatic waves reflected and refracted at the boundary plane between isotropic and arbitrarily anisotropic media are derived from the Maxwell theory both for incidence from the isotropic or from the anisotropic medium. Furthermore, the vectorial amplitudes of the uniradial oscillations are determined. The following special cases of the general formulae are considered: 1. normal incidence, 2. optic axis in direction of the reflected respectively refracted wave in the anisotropic medium, 3. normal and parallel polarization of the partial waves in the anisotropic medium with respect to the plane of incidence.     

Reflexion und Brechung des Lichtes an optisch einachsigen Medien

Reflection and Refraction of Light in Uniaxial Media The formulae for the amplitude relations for the reflection and refraction of plane monochromatic light waves at a plane interface between an isotropic and an arbitrarily anisotropic medium, derived in an earlier paper by the author, are specialized here to the case of uniaxial media. The incidence both from the isotropic and from the uniaxial medium is dealt with. A series of special cases (normal incidence, optical axis parallel or normal to the plane of incidence, transition from uniaxial to isotropic media a.o.) are considered.     

Amplification by reflection from an active medium

The reflectance R of an active (inverted) medium is theoretically shown to be equal to the inverse of the Fresnel reflectance of an absorbing medium when the imaginary parts of the dielectric permeabilities of the active and the absorbing medium differ only in sign. The reflected wave is always amplified (R > 1). The phase shifts upon reflection at the active and the absorbing medium are equal. These results for monochromatic light presuppose a sufficient thickness of the active medium.     

Ionization losses of fast charged particles in an anisotropic medium

The energy losses of fast charged particles in anisotropic media are investigated. The macroscopic Maxwell equations are used to find the electromagnetic field of particles moving according to a given law in an anisotropic medium. A solution in quadratures is obtained for the energy loss of a charge moving at an angle to the optical axis of a weakly anisotropic uniaxial crystal; the result is in the form of a correction to the ionization losses in an isotropic medium. In the case of a medium consisting of anisotropic oscillators, an analytic formula is obtained for the correction: It is inversely proportional to the square of the velocity at particle velocities much less than the velocity of light and tends to zero for ultrarelativistic particles.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 14–19, January, 1978.Finally, it remains to thank O. B. Evdokimov for formulating the problem and for useful discussions.     

Cancellation of simple optical anisotropies without use of a Faraday mirror

We first derive the round-trip Jones matrix for double passage through a reciprocal optical medium by means of reflection off a plane mirror that could be optically anisotropic. We then show that if a medium with only linear birefringence and linear dichroism is placed between a pair of orthogonal quarter-wave plates with principal axes at 45 degrees to that of the medium and the sandwich is placed in front of an isotropic mirror it behaves, under double passage, like an isotropic medium. We describe a simple liquid crystal device that behaves, in reflection, as an isotropic medium whose refractive index can be varied by application of an electric field, thus acting as a phase only modulator for light in any polarization state.     

Anisotropic distribution of quantum‐vacuum momentum density in a moving electromagnetic medium

An isotropic electromagnetic medium becomes gyrotropically anisotropic when it moves, and an anisotropic electromagnetic environment can then be created in this motion‐induced anisotropic medium. One of the most remarkable features is that the quantum vacuum in the anisotropic electromagnetic environment exhibits a nonzero electromagnetic momentum density, since the universal symmetry of the vacuum fluctuation field is broken, and the anisotropic quantum vacuum mode structure is produced because of the symmetry breaking. This would give rise to a noncompensation effect among the four vacuum eigenmodes (i.e., the forward and backward propagating modes as well as their respective mutually perpendicular polarized components), and leads to an anisotropic correction to the vacuum momentum in the moving medium. The physical significance and the potential applications of the anisotropic quantum vacuum are discussed. This quantum‐vacuum effect may be used to develop sensitive sensor techniques and to design new quantum optical and photonic devices.     

Enhanced polarization conversion for an anisotropic thin film

This work presents an explicit expression for the reflection and transmission coefficients of an anisotropic thin film in the general case in which the optical axis and the incident ray are arbitrarily directed in three dimensions. The polarization conversion quantities for reflected light from an anisotropic thin film are calculated and analyzed for two three-layered systems. With light incident from a dense medium, polarization conversion will be enhanced at a particular incident angle that exceeds the critical angle.     

Laser probing of anisotropic ultrathin dielectric films on absorbing materials via differential reflection characteristics

The reflection from an ultrathin anisotropic film on an isotropic absorbing substrate is investigated in the long-wavelength limit. The analytical expressions for the differential reflection characteristics of s- and p-polarized electromagnetic plane waves are obtained. All analytical results are correlated with the numerical solution of the reflection problem on the basis of rigorous electromagnetic theory for anisotropic medium. The possibilities of using the obtained approximate formulas for resolving the inverse problem for ultrathin anisotropic dielectric films upon absorbing substrates are discussed.     

Total internal reflection of a Gaussian light beam

An approximate theoretical model for calculating the reflected and refracted fields of a Gaussian light beam at a plane interface between two isotropic media is formulated on the basis of a Fourier integral. In the vicinity of the critical angle of incidence (for total internal reflection) the model predicts the presence of two refracted beams, one displaced along the interface by an amount equal to the Goos-Hänchen shift; curvature of the phase fronts and nonalignment of the effective directions of energy and phase propagation occur for each beam, as in an anisotropic medium.     

电偶极子在磁各向异性介质中的辐射功率

在经典电动力学框架下对磁各向异性介质中的电磁辐射问题进行研究, 得到了电偶极子在磁各向异性介质中的辐射功率表达式. 当介质为磁各向同性时其结果与文献报道的结果相符合, 验证了推导结果的正确性. 利用本文结果可对电偶极子在磁各向异性介质中的辐射效果做出判断, 而且对于进一步研究磁各向异性介质的电磁特性、更有效地开发利用磁各向异性介质具有实际意义.     

Three-dimensional radiative transfer in an anisotropically scattering, semi-infinite medium: generalized reflection function

Three-dimensional radiative transfer in an anisotropic scattering medium exposed to spatially varying, collimated radiation is studied. The generalized reflection function for a semi-infinite medium with a very general scattering phase function is the focus of this investigation. An integral transform is used to reduce the three-dimensional transport equation to a one-dimensional form, and a modified Ambarzumian's method is applied to formulate a nonlinear integral equation for the generalized reflection function. The integration is over both the polar and azimuthal angles; hence, the integral equation is said to be in the double-integral form. The double-integral, reflection function formulation can handle a variety of anisotropic phase functions and does not require an expansion of the phase function in a Legendre polynomial series. Complicated kernel transformations of previous single-integral studies are eliminated. Single and double scattering approximations are developed. Numerical results are presented for a Rayleigh phase function to illustrate the computational characteristics of the method and are compared to results obtained with the single-integral method. Agreement between the two approaches is excellent; however, as the transform variable increases beyond five the number of quadrature points required for the double-integral method to produce accurate solutions significantly increases. A new interpolation scheme produces accurate results when the transform variable is large.     

Elastodynamics of an axisymmetric problem in an anisotropic liquid-saturated porous medium

The Laplace and Hankel transforms have been employed to find the general solution to the field equations in an anisotropic liquid-saturated porous medium for plain axisymmetric problem, in the transformed form. An application of an infinite space with impulsive force at the origin has been considered to show the utility of the solution obtained. The results of the corresponding problem in isotropic liquid-saturated porous medium can be derived as a special case. To get the solutions in the physical form, a numerical inversion technique has been applied. The results in the form of displacement and stress components have been obtained, numerically and discussed graphically for a particular model.