Showing papers by "A. A. Maradudin published in 1987"

Exact theory of nonlinear p-polarized optical waves.

Abstract: Exact calculations are presented of the properties of nonlinear p-polarized waves propagating along the plane boundary between a nonabsorbing, optically self-focusing, nonlinear dielectric and a nonabsorbing positive, or negative, linear dielectric. A nonlinear polarization is used that arises from a number of causes for both Kerr-like and non-Kerr-like saturating media. In the results given here the linear dielectric is a metal, if negative, and is glass if positive. It is found that the variation of the power flow along the guiding surface with effective index, for negative linear dielectrics, will always exhibit a maximum. For data corresponding to copper bounded by, for instance, a self-focusing nonlinear semiconductor, access to this maximum involves such a large change in the refractive index of the nonlinear material, that it is of no practical interest. In the visible better matching of the metal to a nonlinear material can, in principle, be achieved so this maximum may be reached for fairly modest nonlinear changes in the refractive index. A detailed comparison is made with approximations that are based upon a curtailed form of nonlinearity. At low frequencies, for modest nonlinear changes in the refractive index, the dependence of the power flow curve upon the effective guide index is fairly close to several of the earlier published theories. These include a well-known approximation in which the transverse field component is assumed to be dominant. The neighborhood of the maximum, and beyond, becomes accessible at higher operating frequencies and significant differences from earlier approximations may then occur. For positive linear dielectrics the exact theory shows a strong similarity to many more approximate ones, as expected, but the difference between the TM and TE surface wave behavior cannot be discounted. We present several sample calculations of the power flow together with detailed plots of the field components, the magnitude of the nonlinearity, the effect of nonlinearity, and the behavior of the first integral.

Fresnel-like behavior of guided waves

Abstract: The reflection and transmission of thin-film guided waves incident at variable angles upon a variety of transverse discontinuities are analyzed. A thin film bounded by semi-infinite media is modeled by a thin film bounded by finite media, terminated at shorting planes situated parallel to and a long distance from the film surfaces. The results obtained with this model are checked against previous calculations for normal incidence onto a waveguide–air endface. For nonnormal incidence upon the interface between two waveguides, various interesting phenomena such as guided-wave equivalents of Brewster’s angle, multiple cutoff angles for both guided waves and radiation fields, and intermode conversion are investigated numerically.

Analysis of three theories of scattering of electromagnetic radiation by gratings

Abstract: We report the study of the scattering of p-polarized electromagnetic radiation by gratings of Ag metal, by using perturbation theory, Rayleigh’s method, and an iterative solution proposed by Maradudin [ J Opt Soc Am73, 759 ( 1983)]

Attenuated total reflectivity of semiconductors with wave-vector-linear band splitting

Abstract: We have calculated the attenuated total reflectivity (ATR) of a semiconductor near an excitonic transition in the presence of wave-vector-linear energy-band splitting. The numerical work corresponds to the B(n =1) exciton of CdS, the light being p(TM) polarized in a plane perpendicular to the crystal axis. The ATR spectra reveal two minima: One is a broad minimum between ~~ and coL (the transverse and longitudinal exciton frequencies) and the other is a narrow minimum at -coT. These resonances are interpreted as corresponding, respectively, to the ordinary (essentially local) surface-exciton-polariton and to a new ("nonlocal") surface mode. I. INTRODUCTION Surface-exciton-polaritons in semiconductors with parabolic energy bands have been extensively studied in the past 10 years. In the present work we study surface polaritons in the presence of energy-band splitting which is linear in the wave vector. We focus on the calculation of attenuated total reflectvity (ATR) spectra of the B exciton of CdS, which is the prototype of this kind of nonparabolic dispersion. Energy bands in direct-gap semiconductors are often isotropic and the energies of the corresponding excitons are adequately described by means of a parabolic relation,