Investigation of laser-induced damage mechanisms in back-illuminated cmos detector modules under nanosecond pulsed irradiation

To evaluate the laser-induced damage effects on visible-light imaging systems under realistic operational conditions, a detector module comprising a filter and a back-illuminated CMOS sensor was employed as the target. This study investigates the damage mechanisms induced by nanosecond pulsed lasers at wavelengths of 532 nm and 1064 nm. Initially, a series of experiments were conducted to characterize the typical damage behaviors resulting from laser irradiation. To address the limitations in observing internal thermal and mechanical responses during the experiments, a finite element simulation model was developed to analyze the interaction between the laser and the detector. The simulation enabled visualization of temperature and stress concentration phenomena that are difficult to capture through direct observation, thus providing valuable reference data for damage thresholds. The results from both the experiments and simulations indicate that the dominant damage mechanism is coupled thermo-mechanical failure. The measured multi-stage damage thresholds were 30.06 mJ/cm², 38.93 mJ/cm², 56.20 mJ/cm², and 102.17 mJ/cm² for 532 nm laser irradiation, and 38.62 mJ/cm², 50.09 mJ/cm², 116.31 mJ/cm², and 137.73 mJ/cm² for 1064 nm irradiation.