A study of the spreading of a narrow beam passing through a scattering layer

Measurements of the intensity of radiation propagating on the surface of various light-scattering glasses are presented. The luminosity of the radiation was measured as a function of the distance from the illuminating beam axis. For scattering layers with optical thickness tau = 14-1100, the experimental luminosity distribution is well approximated by the exponential dependence on R. The dependence of the exponential index on tau and the illuminating beam radius is discussed. An analytical model of the distribution of light force at the point of beam spreading is proposed.