Laser-induced damage in a silicon-based photodiode by MHz picosecond laser

Study of the damage characteristics of silicon-based photodetectors is of great significance in improving application performance, but few studies of laser-induced damage have been undertaken on photodetectors irradiated by hundred-ps fiber lasers. In this work, we demonstrate an all-fiber ps-pulsed laser system which outputs a pulse width of 226.5 ps and an average power of 20 W at 2.4 MHz repetition rate, with high beam quality and pulse stability. Experiments use this fiber amplifier to irradiate a silicon-based positive-intrinsic-negative (PIN) photodiode. The changes in detector performance and surface morphology are confirmed by systematic experiments on the laser-irradiated detector. The results show that detection performance was sensitive to laser energy, and the failure damage threshold was about 864 kW cm−2. Based on hydrodynamics theory, we simulated the laser-induced plasma density distribution in a PIN photodiode and studied the thermal and plasma damage mechanisms in the PIN photodiode.