Surface-reflection elimination in polarization imaging of superficial tissue.

A major drawback in polarization gating of light backscattered from tissue is that surface reflections dominate the image. An optically flat plate and matching fluid applied to the tissue surface, combined with off-axis detection, were previously used to address this problem. This approach is often inappropriate or inconvenient for practical use and more importantly can affect the tissue's optical properties. A method is demonstrated that combines images obtained with linearly and circularly polarized light to produce a polarization-gated image that is free from surface reflections and does not require optically flat plates or matching fluid.