Extension of the Stokes equation for layered

Expressions relating the bispectral reflectance of a stack of n fluorescing layers to each individual layer’s reflec-tance and transmittance are derived. This theoretical framework is used together with recently proposed exten-sions of the Kubelka–Munk model to study the fluorescence from layered turbid media. For one layer over a reflecting background, the model is shown to give the same results as a previous model. The extension to n layers with different optical properties allows simulating the bispectral reflectance from a pad of layered turbid media. The applicability of the model is exemplified with an optimization of fluorophore distribution in layered turbi