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开展了HgCdTe晶体的多脉冲热损伤问题的实验研究。采用形貌学方法对脉宽为300 ns重复频率可调的CO2激光器对Hg0.826Cd0.174Te晶体的损伤阈值进行了实验测量,并建立了高重频脉冲CO2激光辐照Hg0.826Cd0.174Te晶体的三维热传导理论模型,分析了激光重复频率和辐照时间对晶体损伤特性的影响。研究表明:300 ns的CO2激光辐照时间大于10 s时,Hg0.826Cd0.174Te晶体的损伤阈值不随辐照时间的增加而改变,其损伤阈值为1.421 4×103W/cm2;激光重频对晶体的损伤阈值的影响较小,损伤阈值主要取决于辐照激光的平均功率密度。SEM损伤结果显示:晶体损伤为热熔损伤,表面未发现由热应力造成的裂缝。理论模型获得的损伤数据和温升规律支持实验结果。该研究可为高重频CO2激光应用、激光防护等提供参考。
The experimental study of multi-pulse thermal damage of HgCdTe crystal was carried out. The damage threshold of Hg0.826Cd0.174Te crystal was experimentally measured by using a CO2 laser with adjustable pulse repetition frequency of 300 ns and a Hg0.826Cd0.174Te crystal with high repetition rate pulsed CO2 laser was established Dimensional heat conduction theory model, the influence of laser repetition frequency and irradiation time on the damage characteristics of the crystal was analyzed. The results show that the damage threshold of Hg0.826Cd0.174Te crystal does not change with the increase of irradiation time and the damage threshold is 1.421 4 × 103W / cm2 when the irradiation time of 300 ns CO2 laser is more than 10 s. The damage threshold is less affected. The damage threshold mainly depends on the average power density of irradiated laser. SEM damage results show that: Crystal damage is hot melt damage, the surface is not found by the thermal stress cracks. The damage data obtained by the theoretical model and the law of temperature rise support the experimental results. This study provides a reference for high-frequency CO2 laser applications and laser protection.