Beam reflection from lossy dielectric layers

Abstract

A beam incident upon a slightly lossy layered dielectric structure at special (phase-matched) angles displays abnormal absorption and lateral beam shift on reflection. The amplitude of the reflected beam can be calculated either by a conventional transform technique or by a quasi-particle method. Different wave-number (k) expansions of the reflection coefficient may be employed for calculation of reflected beam properties. The convergence of these expansions is limited by the presence of poles and zeros and by the rapidity of dispersion in k of the reflection coefficient. The series expansions used in the quasi-particle method are not limited by the zeros and converge better for far fields than for fields on the reflecting surface; moreover, they permit faster numerical calculation of beam properties.