Depth-resolved degree of polarization of backscattered light and two-dimensional Mueller matrices of biological tissue measured by optical coherence tomography

Mueller matrices provide a complete characterization of the optical polarization properties of biological tissue. A polarization-sensitive optical coherence tomography (OCT) system was built and used to investigate the optical polarization properties of biological tissues and other turbid media. The apparent degree of polarization (DOP) of the backscattered light was measured with both liquid and solid scattering samples. The DOP maintains the value of unity within the detectable depth for the solid sample while the DOP decreases with the optical depth for the liquid sample. Two-dimensional depth-resolved images of the full Mueller matrices of biological tissues were measured with this system. These polarization measurements revealed some tissue structures that are not perceptible with standard OCT.