Effect of laser pulse width (ns-fs) on laser-induced damage thresholds of a CMOS photodetector

This study investigated the effect of laser pulse width on the laser-induced damage threshold of a CMOS photodetector with fs-ns laser pulsed width arranged by using the two-temperature model (TTM) and Fourier heat transfer models, and experimental verification was conducted. The simulated results show that for pulse widths 10ps<τ<100ps, both the TTM model and the Fourier heat conduction model are used. In the transition regime, the TTM is adopted for pulse widths shorter than 60 ps, and the Fourier heat conduction model is adopted for pulse widths larger than 60 ps. Over the investigated pulse width range of 50 fs to 300 ns, the thermal damage threshold of the CMOS photodetector is increased with laser pulse width. By accounting for thermal diffusion effects, the fitted scaling law is obtained as F_th∼τ^0.41. To validate the simulated results, the laser-induced damage experiments of the CMOS photodetector are performed using 50 fs and 10 ns pulsed lasers and the results compared with existing research. The experimental damage thresholds agree with the theoretical predictions and the proposed laser-induced damage threshold-pulse width scaling law by accounting the wavelength-specific material parameters. This work provides theoretical support for assessing and mitigating laser-induced damage in the CMOS photodetector.