Polarization grating based on diffraction phase microscopy for quantitative phase imaging of paramecia

This study presents a polarization grating based diffraction phase microscopy (PG-DPM) and its application in bio-imaging. Compared with traditional diffraction phase microscopy (DPM) of which the fringe contrast is sample-dependent, the fringe contrast of PG-DPM is adjustable by changing the polarization of the illumination beam. Moreover, PG-DPM has been applied to real-time phase imaging of live paramecia for the first time. The study reveals that paramecium has self-helical forward motion characteristics, or more specifically, 77% clockwise and 23% anti-clockwise rotation when moving forward. We can envisage that PG-DPM will be applied to many different fields.