Theoretical model of the shift of the Brewster angle on a rough surface

A physical mechanism is proposed for the explanation of the angular shift of the Brewster angle induced by a rough surface as recently discovered by Saillard and Maystre [J. Opt. Soc. Am. A 7, 982 (1990)]. An explicit formula giving the angular shift as a function of the correlation length sigma and the mean-square departure from the flat surface delta is derived. It is shown that in the case of a rough surface, a minimum rather than a true zero is obtained for the reflection factor.