<title>Coherence in single and multiple scattering of light from randomly rough surfaces</title>

Abstract

One of the most interesting phenomena associated with the scattering of light from a randomly rough surface is that of enhanced backscattering. This is the presence of a well-defined peak in the retroreflection direction in the angular distribution of the incoherent component of mean scattered intensity of the light scattered from such a surface which is due primarily to the coherent interference of each multiple reflected optical path with its time-reversed partner. It is an example of a broader class of multiple scattering phenomena that goes under the name of weak localization. Not all of the manifestations of weak localization in the interaction of light with a randomly rough surface are in backscattering. It was recently shown that the average diffuse intensity from randomly rough surfaces with even symmetry can be enhanced or reduced in the specular direction due to the constructive interference between correlated pairs of scatters. In this paper we will present recent theoretical analysis and experimental results that cover four kinds of enhancement: the enhanced backscattering, the enhanced transmission, the enhanced specular, and the enhanced refraction for 1-D and 2-D surfaces. These are manifestations of coherent effects that remain after ensemble averaging.