Light-scattering measurements from dense optical systems

Abstract

We report on the effects of dense optical systems on the static and dynamic properties of laser light. The measurements of the angular irradiance distribution as a function of the optical density and the size of the scattering centers confirm previous measurements performed by Woodward. Our study of the scattered irradiance correlation function indicates that, in the presence of multiple scattering, the relaxation time may be significantly smaller than that predicted on the basis of the single-particle Brownian model. Furthermore, the angular dependence of the irradiance relaxation time deviates from the usual proportionality to the inverse square of the momentum transfer. We discuss a number of tests that have been performed to minimize the possibility that some of our conclusions could be affected in part by particle aggregation, surface charges, and depolarization of the scattered light.