Scattering and diffusion of a beam wave in randomly distributed scatterers

Diffusion theory is applied to the transmission of an optical beam through randomly distributed particles, and the theoretical calculations are compared with experimental data for an optical beam at 0.6 μm propagating through latex scatterers of sizes 0.109 and 2.02 μm. It is shown that, for particles small compared with the wavelength, the diffusion theory gives good agreement with experimental data; whereas for particles large compared with the wavelength, the diffusion theory is applicable when the optical depth is greater than about 20. For shorter optical depth, experimental results are also compared with the first-order scattering theory.