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/(3µs′+µa) . One can reconcile this result with recent work advocating D=c/3µs′ by noting that the diffusion equation must be correspondingly changed to a telegrapher’s equation.
© 1998 Optical Society of America
(170.3660) Medical optics and biotechnology : Light propagation in tissues
(170.5270) Medical optics and biotechnology : Photon density waves
(290.1990) Scattering : Diffusion
(290.7050) Scattering : Turbid media
D. J. Durian, "The diffusion coefficient depends on absorption," Opt. Lett. 23, 1502-1504 (1998)