Simple and versatile analytical model for continuous-wave fluorescence in multilayered turbid media under the diffusion approximation

In this work, we introduce a simple analytical approach to compute the steady-state diffuse fluorescence in media formed by an arbitrary number of vertically stacked layers, where the absorption coefficient of the fluorophore in each layer is given. The expressions derived here are based on already existing solutions to the diffusion equation, under the assumption that the optical parameters (including the absorption coefficient) depend neither on the excitation nor on the emission wavelengths. Comparison with MC simulations and with phantom experiments demonstrate the feasibility of our analytical model. Further, we discuss the validity of the theory under diffusive and non-diffusive regimes.