In the literature one can encounter at least two different radiative transfer equations for media with spatially varying refractive indices. These are the results of Ferwerda [J. Opt. A Pure Appl. Opt. <b>1</b>, L1 (1999)] and Tualle and Tinet [Opt. Commun. <b>228</b>, 33 (2003)]. Accordingly, two different diffusion approximations are derived from these two radiative transfer equations. I reconsider the derivation of the radiative transfer equation in a medium with an inhomogeneous refractive index and confirm the result of Tualle and Tinet. In the diffusion approximation, a simple analytical solution has been found for the steady-state illumination of a nonabsorbing turbid medium with a varying refractive index.
© 2004 Optical Society of America
(030.5620) Coherence and statistical optics : Radiative transfer
(170.3660) Medical optics and biotechnology : Light propagation in tissues
(290.1990) Scattering : Diffusion
(290.7050) Scattering : Turbid media
Margarita L. Shendeleva, "Radiative transfer in a turbid medium with a varying refractive index: comment," J. Opt. Soc. Am. A 21, 2464-2467 (2004)