Dispersión de luz por la superficie rugosa de una película excitónica delgada sobre un substrato metálico

Abstract

The effect of the spatial dispersion of a semiconductor film, having a rough free surface and overlying a metal, on the differential reflection coefficient is investigated theoretically. The investigation is carried out near exciton resonance where the nonlocality is strong and leads to the generation of additional polaritonic waves. Applying a first-order perturbation theory, we calculate the angular and frequency dependencies of the differential reflection coefficient for the case of one-dimensional roughness. The spectra of diffuse reflection for CuCl on a Al metal for incident light with $s$-polarization exhibit pronounced resonances (peaks) at frequencies satisfying Fabry-Perot conditions for the additional polaritonic modes. These conditions also correspond to the size quantization of the exciton's translational motion. Our results show the usefulness of the spectra of diffuse reflection for studying the excitation of quantized polaritonic modes in nonlocal films.