OPTICAL-PROPERTIES OF SEMICONDUCTOR SUPERLATTICES IN THE FAR INFRARED

In the far infrared, superlattice dielectric functions can be well represented by an effective-medium model. The overall symmetry of a superlattice is uniaxial, and each of the principal components of the resulting dielectric tensor typically contains a different series of resonances. Here we examine some consequences that are of importance to many of the spectroscopy experiments that are undertaken. We describe sharp Brewster modes near longitudinal frequencies in p-polarized oblique incidence reflectivity and give details of guided wave and surface modes, including interface polaritons at the superlattice-vacuum interface. After discussing the basic optical principles we examine their application to the measurement of phonon confinement parameters.