Reflectance statistics from a thin weakly disordered optical media: application to detection of structural alterations in cells/tissues

Abstract

A linearized stochastic model is introduced to describe light-scattering from a thin weakly disordered optical medium with a mean refractive index (RI) different from that of the uniform surrounding medium. The parameters are chosen suitably to study scattering from biologically relevant cell/tissue samples using partial wave spectroscopy technique. Closed-form analytical results are derived for the statistics of the reflected light. We show in detail how they can be directly compared with experiments to extract the sample thickness and mean RI with the aim of determining the structural disorder parameter - changes in which are useful biological markers for disease related abnormal alterations in the intracellular structures. A strong spectral dependence of the auto-correlation function is found arising from the interaction between disorder scattering and thin-film interference leading to a new decorrelation lengthscale.