Moving grating-based laser heterodyne digital holographic microscopy system for measuring dynamic phase of living cell attachment

We propose a laser heterodyne digital holography microscopy system based on a moving grating, which uses the Doppler principle between a moving grating and beam to achieve a low-frequency bias between the diffracted beams, abandoning traditional heterodyne digital holography that requires multiple acousto-optic modulators. The dynamic phase distribution obtained using the laser heterodyne digital holography phase-reconstruction algorithm was more realistic and analyzable than the results of the angular spectrum algorithm. The structure and algorithm were used to capture the shape characteristics of mouse fibroblasts after ~2 h of incubation (37°C, 5% CO₂), and the dynamic phase distribution of the cells was monitored in real-time during the attachment process. The system proposed in this study, with its high spatial resolution and high-precision phase measurement capability, is suitable for both static and live cells.