Stokes polarimetry imaging of rat-tail tissue in a turbid medium using incident circularly polarized light

BACKGROUND AND OBJECTIVES: We describe a Stokes polarimetry imaging technique that quantifies the polarization properties of remitted light backscattered from a sample. STUDY DESIGN/MATERIALS AND METHODS: Right- and left-circularly polarized near-infrared light was used to illuminate rat-tail tissue embedded in turbid gelatin. RESULTS: The degree of linear polarization (DoLP) and degree of circular polarization (DoCP) image-maps indicate that increasing the depth of the rat tail within the turbid medium and varying the rat-tail geometry and orientation relative to the light source affected the contrast between structures and adjacent tissue layers. CONCLUSION: Stokes polarimetry imaging shows that the intervertebral discs and soft tissue regions of rat tails strongly depolarize incident circularly polarized light. Tendon regions remit light with a more linear form due to birefringence. Both DoLP and DoCP image-maps provide contrast between tissue structures. When differentiating between unpolarized light and light with low DoCP or DoLP, the polarization of backscattered light from the turbid medium must to be taken into consideration.