A note on surface magnetoplasmons in semiconductors

The results of Brion et al. [Phys. Rev. Lett.28, 1455 (1972)] are reinterpreted to predict, in facile manner, the type of inequalities that need to be satisfied by the surface parameters for the existence of gaps and multiple branches in the dispersion curves for surface waves along the interface of a semiconductor-semiconductor structure.     

The linear dispersion coefficient of surface magnetoplasmons

The dispersion of surface magnetoplasmons supported on a semiconductor-vacuum interface which is normal to an applied magnetic field is investigated. It is assumed that the surface possesses a depletion layer and that the dispersion is of hydrodynamic origin. Dimensionless numerical results are obtained for the magnetic field dependence of the linear dispersion coefficient with special reference being given to n-type InSb.     

Demonstration of Faraday anomalous dispersion optical filter with reflection configuration

A narrow linewidth Faraday anomalous dispersion optical filter(FADOF)with reflection configuration is achieved for the first time based on the cesium(Cs)ground state 6S_1/2 to the excited state 6P_3/2 transition at 852 nm.Compared with the conventional FADOF with transmission configuration,reflection-type FADOF can greatly improve the transmittance of optical filter under the same experimental parameters,because it allows signal light to go and return through the atomic vapor cell.In our experiment,peak transmittance at Cs 6S_1/2 F=4-6P_3/2 transition is 81%for the reflection-type FADOF,and while 54%for the transmission-type FADOF when the temperature of Cs vapor cell and the axial magnetic field are 60℃and 19 G.The idea of this reflection-type FADOF design has the potential to be applied to the FADOF operating between two excited states to obtain higher transmittance.     

On the observation of surface magnetoplasmons

It is shown that, of the two techniques (grating or prism coupling) proposed for the observation of surface magnetoplasmons, the prism technique appears far superior. An analytic reflectivity formula is presented which will be necessary in the analysis of surface magnetoplasmon experimental data.     

On the dispersion relation of magnetoplasmons in a planar graphene-based superlattice

The dispersion relation for magnetoplasmons in a planar superlattice with periodically alternating regions of gapless and gapped modifications of graphene has been derived within the frame of the random-phase approximation. The contribution of virtual transitions between the lower electron miniband and the upper hole miniband to the polarization operator has been taken into account in addition to the contribution of virtual intra-miniband transitions.     

A note on the plasma dispersion function

In the gas laser theory for non-doppler broadening, the plasma dispersion function is often considered to be an antisymmetric function: Z(-μ) = -Z(μ). We shown here that this property is not correct, because the usual integral definition for the plasma dispersion function is not entire in the complex plane.     

A direct analysis of the dispersion equation in birefringent optical fibres

Weakly-guiding, anisotropic step-index fibres are considered in the case where the permittivity tensor is everywhere diagonalized in the axes of the fibre. A method is shown which allows one to derive a mode and its dispersion equation with arbitrary accuracy in terms of the powers of the weak-guiding parameter. The method is applied to the derivation of the leakage loss of they-polarized LP₀₁ mode when _x>_y.     

A note on surface stress and surface tension and their interrelation via Shuttleworth’s equation and the Lippmann equation

Some aspects of the thermodynamics of solid surfaces, in particular with respect to the surface stress, f, and surface tension, γ, including the case of solid electrodes, are examined in view of their controversial discussion in part of the recent literature. By inspection of the phenomenology that requires a distinction between f and γ, and of a toy model designed to highlight the underlying fundamental science, it is shown that some of the recent publications give misleading conclusions. These include [V.A. Marichev, Surf. Sci. 600 (19) (2006) 4527; E.M. Gutman, J. Phys. Condens. Matter. 7 (48) (1995) L663; D.J. Bottomley, T. Ogino, Phys. Rev. B 63 (2001) 165412]. In spite of claims to the contrary, the validity of the equations of Shuttleworth, Lippmann, and Couchman and Davidson is not impaired by the arguments of the aforementioned articles.     

A note on the Boltzmann equation for hard spheres

A simple form of the Boltzmann kinetic equation for hard spheres is proposed.     

Effect of the surface integral in the torque equation of the electromagnetic angular momentum on the Faraday rotation

A circularly polarized plane wave of infinite transverse extent (δ = ∞) has no spin angular momentum, while a realistic light does carry it. This paradox originates from the presence (δ = ∞) and absence (δ ≈ 0) of the surface integral in the total angular momentum J. The same holds for the torque equation of dJ/dt, so that δ is also connected with the relative Faraday rotation angle Θ_F/θ_F when a radius (a) of a cylindrical medium with optical activity is only a little larger than that (b) of light beam, where Θ_F is the Faraday rotation angle and θ_F is the intrinsic Faraday rotation angle of a medium. It is shown here that it is possible to estimate δ for a realistic light from the drastic variation in Θ_F/θ_F near b/a = 1.     

Theory of damped surface magnetoplasmons in n-type InSb

A theoretical investigation of surface magnetoplasmons in n-type InSb has been carried out with the effect of damping taken into account. Part of the investigation included surface magnetoplasmons interacting with surface optical phonons. The calculated dispersion curves show backbending, in contrast to the situation were damping is neglected. In addition, there are gaps in the dispersion curves for certain frequency ranges.     

Interaction of surface magnetoplasmons and surface optical phonons in polar semiconductors

A theoretical investigation has been carried out of surface polaritons associated with surface magnetoplasmons coupled to surface optical phonons in polar semiconductors. The coupled mode frequencies are calculated for several orientations of the magnetic field relative to the surface and the direction of propagation in the large wave vector (unretarded) limit. Dispersion curves are calculated for the configuration in which the magnetic field is parallel to the surface and is perpendicular to the wave vector. Experimental possibilities for observing the interaction effects are discussed.     

A note on loop-soliton solutions of the short-pulse equation

It is shown that the N-loop soliton solution to the short-pulse equation may be decomposed exactly into N separate soliton elements by using a Moloney-Hodnett type decomposition. For the case N=2, the decomposition is used to calculate the phase shift of each soliton caused by its interaction with the other one. Corrections are made to some previous results in the literature.     

A note on the solution of a spinor equation

An equation of spinor algebra, which is specified by two positive integers,M andN, is solved by relating it to the problem of integrating a two-dimensional Hamiltonian homogeneous polynomial system of ordinary differential equations, whose degree isN}-1. The case in whichN=1 reduces to a well-known result of spinor algebra. The caseM=N=4 is of relevance in the study of symmetry operators of Maxwell's equations on a curved space-time. It is also shown, using spinor notation, that the first integral for a general two-dimensional Hamiltonian system of ordinary differential equations (whether polynomial or analytic) is determinable in a purely algebraic manner, i.e., by using no integration.     

A note on surface plasmons

We consider the dispersion of the surface plasmons in an approximate RPA. It is shown that the usual linear dependence of the frequency on the wave vector is valid in the high density limit.     

A note on the equation of state for systems that undergo valence changes

By considering the effects of valence changes on the parameters that determine the cohesive energy of samarium monochalcogenides, we discuss the equation of state for these systems and provide a basis for the understanding of the anomalous pressure dependence of the compressibility that is found experimentally.     

A note on the derivation of the Schrödinger-Langevin equation

It is shown that the dynamics of open systems interacting with a chaotic environment can be formulated in a quantum mechanical scheme by means of Nelson's stochastic quantization procedures. As a result, a wave equation for a particle in the chaotic environment is found to be of the Schrödinger-Langevin type associated with an additional nonlinear and random potential.