Tunable Polarization Imaging System With Liquid Crystal Polarization Grating for Biomedical Tissue Analysis

We present a tunable polarization imaging system (TPS) incorporating a liquid crystal polarization grating (LCPG) and a quarter-wave plate (QWP). TPS overcomes low diffraction efficiency and insufficient flexibility in polarimetric imaging, leveraging the LCPG's high diffraction efficiency (> 98%) and polarization control via LCPG-QWP combination. Using the TPS, we conducted comparative experiments on five types of pathological tissue sections, employing six types of polarized light alongside unpolarized light (serving as the control group), and acquired polarization images. Furthermore, we applied multidimensional data analysis methods to analyze and compare the obtained polarization images. The results show that polarized light significantly enhances texture contrast in diseased tissues, achieving a 284% increase compared to acquisitions using unpolarized light, while enabling robust discrimination between benign and malignant tissues. TPS, characterized by its high efficiency, compact design, and compatibility with existing equipment, shows great potential for label-free, pathological-section-based early cancer diagnosis.