Facet model for photon-flux transmission through rough dielectric interfaces.

When a photon flux is incident upon a rough interface that separates media with different refractive indices, the interface roughness influences the angular distribution of the transmitted flux. For the case of very rough surfaces with slopes of the order of unity, we find that a simple facet model is sufficient to describe the main features of the f lux-transmission behavior. We demonstrate the effect observed by Nieto-Vesperinas et al. [Opt. Lett. 15, 1261 (1990)] for plane-wave incidence, that the interface roughness tends to suppress the refractive-index contrast. In addition, for cases in which the incident flux is distributed in angle, we find that the direction of maximum transmitted flux can be predicted from the surface roughness.