Non-diffusive behavior of laser beams in a highly scattering medium

We have solved the Boltzmann equation for a turbid medium that is character ized by a hi-directional scattering phase function for two different geomet ries. We investigate how the photon-density waves that are excited by an am plitude modulated laser beam propagate through an infinitely extended mediu m and compare the results with the scattering properties of a finite medium . Large deviations are-obtained between the diffusion approximated solution and the exact Boltzmann prediction for large modulation frequencies.