Effect of plasma waves on the optical properties of metal-insulator superlattices

Abstract

We develop a simple transfer-matrix formalism in order to obtain the dispersion relation of the electromagnetic normal modes of an infinite insulator-metal (or highly doped semiconductor) superlattice, taking into account the presence of plasma waves, spatial dispersion, and retardation. We also calculate the p-polarized reflectance and give analytical expressions for the surface impedance, reflection amplitude, and the dispersion relation of the surface modes of a semi-infinite superlattice. We find resonant features corresponding to the propagation of guided plasma waves in the metal layers coupled by transverse fields in the insulating layers. This coupling also yields new bulk modes in regions where propagation would not be allowed without spatial dispersion.