Quasi-holographic solution to polarization-sensitive optical coherence tomography acceptable to nonlaboratory applications

Abstract

Experimental proof-of-concept is presented for a quasi-holographic solution to polarization-sensitive optical coherence tomography (PS OCT). Due to decoupling between the reference and sample beams by polarization, the solution seems acceptable to acquisition and communication of optical data in the nonlaboratory environment. The nonlab environment implies uncontrollable disturbances, e.g., temperature changes and mechanical effects happening under shop testing in industry or routine examinations in common clinics and hospitals. For mapping the collagen-related depolarization ratio of light backscattered from the human dermis, a phenomenological model is evolved from the theory of light depolarization in crystalline polymers. The model yielded a simplified intensity-based estimation algorithm. The design concept and the model rely on a submillimeter tumor thickness as a proofed prognostic factor and an important criterion for complementary functional diagnostics of skin cancers in their early phase. Choice of the model is inspired by similarity of structural and optical properties between liquid-crystal collagen fibers in the dermis and birefringent crystalline lamellae in some polymer materials. The model gives a plausible interpretation of a peculiarity of cumulative birefringence in the abnormal skin dermis. Following a top-down approach to design, the authors attempt to contribute to bridging the gap between practitioners' concerns and academic studies.