高重频CO2激光损伤HgCdTe晶体的数值分析

针对CO2激光作用下HgCdTe晶体的损伤问题进行了数值分析。首先，建立了高重频CO2激光损伤Hg0．784 Cd0．216 Te晶体的三维热传导物理模型；然后，利用有限元方法计算了单脉冲和高重频CO2激光作用下，Hg0．784 Cd0．216 Te晶体的损伤阈值；最后，分析了激光重频以及辐照时间对晶体损伤阈值的影响。研究结果表明：单脉冲激光辐照下，晶体的损伤阈值为64.5 J/cm2；高重频（f＞1 kHz）激光辐照下，激光重频的改变对晶体损伤阈值的影响较小，损伤阈值应由平均功率密度表征，且与辐照时间密切相关；辐照时间的增加，可以有效地减小晶体的损伤阈值，当激光辐照功率密度＜1.95 kW/cm 2时，不会发生晶体损伤。研究结果对高重频CO2激光在激光加工以及激光防护的应用方面具有指导意义。

Numerical analysis of HgCdTe crystal damaged by high repetition frequency CO2 laser

To obtain thermal damage characteristics of the HgCdTe crystal irradiated by a CO 2 laser, the theo-retical model of Hg0.784 Cd0.216 Te crystal damaged by the high repetition frequency CO 2 laser was developed, and then the damage thresholds of Hg 0.784 Cd0.216 Te crystal irradiated by a single pulse laser and a high repeti-tion frequency laser were calculated based on the finite element method .Finally, the effect of irradiation time and laser repetition frequency on the damage thresholds was analyzed .The results show that the damage threshold of the crystal radiated by a single pulse laser is 64.5 J/cm 2 .In the high repetition frequency （f〉1 kHz） CO2 laser irradiation, the damage threshold of the crystal mainly depends on the laser average power density and irradiation time, and is independent of the laser repetition frequency .With the increase of irradia-tion time, the damage threshold can effectively be reduced .When the laser average power density is less than 1.95 kW/cm 2 , the crystal damage will not occur .The conclusions have a reference value for laser processing and protection.