Backscattering of a picosecond pulse from densely distributed scatterers

A theoretical and experimental study of the backscattering characteristics of a picosecond pulse scattered from a dense diffusing medium is presented. The theory uses a diffusion solution to the time-dependent equation of radiative transfer and the formulation of a picosecond range-gating technique. The experimental system consists of a high-power laser range-gating system, based on a picosecond Kerr-effect shutter. The results of experiments carried out on aqueous solutions of latex microspheres agree well with the theoretical calculations, not only in the pulse shape but in the relative magnitudes of the pulse height for different particle sizes and concentrations.