Study on the responsivity of individual cells in silicon-based quadrant detectors irradiated by 1064nm continuous laser

In this study, a continuous-wave laser at a wavelength of 1064 nm was employed to irradiate a single cell of a quadrant photodetector (QPD). Subsequently, the responsivity changes of each individual cell following irradiation were measured and analyzed. The research results show that when a single cell is irradiated, the response sensitivity of that cell gradually decreases as the laser power density increases. With further increases in laser power density, the response sensitivities of the other cells also begin to decline. This phenomenon occurs because localized overheating causes lattice damage and material defects, and even melting, leading to a decrease in the response sensitivity of the irradiated cell. However, the thermal effects generated by the laser do not affect the response sensitivities of the other cells initially; only when the laser power density increases further does the thermal energy generated by the laser irradiation diffuse to the other cells through heat carriers, causing defects in these cells as well, and thus decreasing their response sensitivities. This study provides a theoretical basis and guidance for improving the precision and efficiency of laser processing and positioning technologies.