Numerical simulation of high-power density CO2 laser ablation of HgCdTe

A two-dimensional coupled model of phase transition, heat transfer and vaporization ablation of laser-irradiated HgCdTe materials has been developed for the first time using finite element analysis to simulate the behavior and characteristics of melting, phase transition and ablation of HgCdTe materials irradiated by a COQ laser with a wavelength of 10.6 mu m at different laser powers. The results demonstrate that an increase in power density results in an exponential decrease in the time required for HgCdTe to reach the melting and gasification temperatures. The corresponding temperature points can be reached in the order of nanoseconds. During the heating phase, the increase in temperature results in a gradual enlargement of the melt pool in the ablation crater, with the minimum thickness of the melt pool occurring in the central region of the ablation. However, the diameter of the ablation crater tends to stabilize after the spot size is reached. An increase in power density results in a reduction in the size of the molten pool at the center of the ablation crater, while the size of the molten pool at the edges remains relatively constant. Once the laser irradiation ceases, the melt pool near the ablation crater's center is initially dissipated because of heat generated by the material's gasification process. In contrast, the melt pool at the periphery persists until the final stages of dissolution. The simulation results demonstrate that at a power density of 2.6 MW/cm2 , 2 , the ablation crater depth is approximately 12 mu m, which is enough to penetrate the HgCdTe layer of the detector. These results provide a foundation for further research on the damage mechanisms of HgCdTe detectors.