We give a sufficient condition for the field scattered from a surface (<i>S</i>) illuminated by a laser beam to be a stationary gaussian field. This condition is fulfilled for the optical shot noise. As an example we calculate the spectrum of the field scattered from a granular surface. We show that it does not depend on the statistical properties of (<i>S</i>) when the number of grains tends to infinity.
MARTINE ROUSSEAU, "Statistical Properties of Optical Fields Scattered by Random Media. Application to Rotating Ground Glass," J. Opt. Soc. Am. 61, 1307-1316 (1971)