Birefringence measurement of biological tissue based on polarization-sensitive digital holographic microscopy

We present a polarization-sensitive digital holography to measure the birefringence of biological tissues with complex structures. The birefringence measurement system is established by incorporating the modified Mach–Zehnder interferometer and lab-developed software. Normal and cancerous bladder tissue samples are measured by using the proposed experimental system. The polarization-dependent phase-shifted holograms are recorded by rotating the polarizer. Moreover, the hybrid reconstruction and least-square unwrapping algorithms are used to extract phase information of biological tissues at different polarization states. The birefringence of tissue is obtained from the above-phase distributions. The results show that polarization sensitivity exists in the normal bladder tissue and cancerous bladder tissue, and the median birefringence value of the cancerous tissue is significantly higher than that of the normal tissue. These results will provide reference for pathological research and clinic diagnoses.