Light diffusion in N-layered turbid media: frequency and time domains.

We deal with light diffusion in mismatched N-layered turbid media having a finite or an infinitely thick N'th layer. We focus on time-resolved light propagation in both the frequency and time domains. Based on our results for the steady-state domain, solutions of the N-layered diffusion equations in the frequency and time domains are obtained by applying the Fourier transform technique. Different methods for calculation of the inverse Fourier transform are studied to validate the solutions, showing relative differences typically smaller than 10(-6). The solutions are compared to Monte Carlo simulations, revealing good agreement. Finally, by applying the Laplace and Fourier transforms we derive a fast ( approximately 1 ms) and accurate analytical solution for the time domain reflectance from a two-layered turbid medium having equal reduced scattering coefficients and refractive indices in both layers.