3D-printed compact snap-shot lensless birefringence microscope based on digital on-axis holography

Birefringence, an inherent optical characteristic in anisotropic materials arising from structural anisotropy of materials or mechanical stress, plays a major role in understanding the microscopic structures of anisotropic materials and has been widely studied in biology and medicine. To achieve birefringence imaging of dynamic objects, various snap-shot quantitative birefringence imaging techniques relying on lenses have been developed, which are bulky and restricted to laboratory settings. In this paper, we present a 3D printed single-shot lens-free polarization holographic microscope based on digital on-axis holography, in which a birefringent beam-displacer is introduced in a conventional lens-free imaging system to realize a spatial multiplexing polarization hologram recording. Based on our proposed reconstruction algorithm, quantitative polarization holographic images and birefringence parameter distributions of dynamic samples can be retrieved simultaneously. The relevant experimental results demonstrated the feasibility of our proposed polarization imaging system, which exhibits higher stability and greater immunity to mechanical vibration and air fluctuation, and it has the potential for imaging dynamic specimens, especially in resource-limited environments.