Tissue polarimetric discrimination analysis of skin and colon histological samples

Tissue polarimetry provides a non-invasive, fast and relatively cheap differentiation of healthy from tumor tissues. This approach uses the different manner in which healthy tissues depolarize light, compared to the tumor ones. In extremely scattering optical media, such as biological tissues, light undergoes multiples scattering events, leading to changes in the two orthogonal components of the electric field E_x, E_y and a phase shift between them, which partially or fully depolarizes the initial polarization. When the size of the scattering particles is less than the wavelength of light (d < λ), then the linear polarization is preserved better. On the contrary, when the size of the scattering particles is greater than the wavelength of light (d > λ), then the circular polarization is preserved better. Measuring the Stokes parameters of light with linear and circular polarization and wavelength λ = 635 nm, diagnostic conclusions might be obtained for the histological condition of the samples, which are in agreement with the analysis of the pathologists. Moreover, this approach optimizes the differentiation based on polarization properties for the investigated soft tissues samples.