光学材料在激光辐照下熔化、汽化相变烧蚀数值模拟

Simulation of optical material under laser irradiation: melting,vaporization and ablation

对光学材料激光辐照下传热、相变烧蚀,采用有限差分全隐格式,在相变区采用潜热叠加到比热的方法,编制了一维程序。研究了光学材料Si在不同功率密度、不同脉宽的激光辐照下的传热、相变烧蚀速度和深度。计算结果表明,相变烧蚀速度和深度定量决定于激光能量沉积率大小,也取决于热传导能量损失和相变潜热耗能之间的相互竞争关系。

A 1-D implicit finite difference program is coded to simulate heat conduction and phase change of optical materials under laser irradiation, with the latent of phase change being equivalently incorporated into the heat capacity in a temperature range around the phase change points. Velocities and depths of phase change and ablation of silicon are calculated under different laser intensities and pulse durations, which are found to be determined by the competition among the velocity of laser energy absorption, heat conduction, and latent of phase change of the material.