Multi-color backscattering Mueller matrix imaging on thick fresh tissues and on living nude mice skin

It has been demonstrated in many biomedical applications that polarization imaging is capable of probing the characteristic microstructural features of complex biological specimens quantitatively and non-invasively. In a recent study, we carried on backscattering Muller matrix imaging on living nude mice skin using oblique illumination by a 633nm LED light source. We quantitatively measured how the anisotropy properties of the living mice skin changes as functions of the UV exposure time. The time course features provide vital clue for the mechanism of UV damage and the effectiveness of sunscreen for reducing such damage. In this work, we report an upgraded system with LED light sources of five different colors ranging from blue to red. The system is calibrated by taking multi-color Mueller matrix images using a single set of rotating achromatic quarter-wave plates. In both in situ applications on living nude mice skin and ex vivo imaging of thick fresh tissue samples, we demonstrated that the multi-color polarized light backscattering measurements are able to reveal more details on the microstructure of the sample, particularly helpful in separating different effects due to photon scattering and propagation.