Spatial dispersion effects on the optical properties of an insulator<i>–</i>excitonic-semiconductor superlattice

Abstract

A transfer-matrix formalism is developed to study the effects of spatial dispersion in the optical properties of a superlattice made up by alternating an excitonic semiconductor with an insulator. We obtain the dispersion relation of the electromagnetic normal modes of an infinite superlattice and the reflectance for p-polarized light incident on a semi-infinite superlattice in the vicinity of an excitonic transition. Calculations are presented for the semiconductor CdS, and the results obtained with different choices of the additional boundary conditions and with the classical local model are compared. They display a very rich structure which is interpreted in terms of the different guided and surface waves supported by the semiconductor layers.