title: The diffusion coefficient depends on absorption.
abstract: The diffusion approximation is widely invoked to model the propagation of light in turbid media. When absorption is not weak in comparison with scattering, there is currently a controversy as to if, and how, the diffusion coefficient depends on absorption. Here it is shown that better agreement with random walk simulation is obtained if the photon-diffusion coefficient is taken as D=c/(3micro(s)(')+micro(a)) . One can reconcile this result with recent work advocating D=c/3micro(s)(') by noting that the diffusion equation must be correspondingly changed to a telegrapher's equation.
authors: Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095-1547, USA.
authors: D J
authors: DJ
authors: Durian