对基于KTA (KTiOAsO4, 砷酸钛氧钾)晶体的中红外2 μm光参量振荡器的输入镜膜层损伤现象进行了初步分析及对比实验研究, 表明薄膜缺陷导致的热效应是造成输入镜膜层损伤、抗损伤阈值低的主要原因, 同时发现由于腔镜失调等原因造成的腔内残余1.06 μm激光是造成膜层损伤的主要来源, 这些结果对改进光参量振荡器系统设计、进一步提高2 μm激光输出能量具有一定的指导作用。

The optical coating damage of input mirror of middle infrared 2 μm KTA optical parametric oscillator is analyzed preliminarily, and the comparative experiments are performed to identify its cause. It shows that thermal effect induced by optical coating defect is the main reason for the low anti-damage threshold of input mirror coating. Meanwhile, it also shows that the main source of coating damage is remnant 1.06 μm laser in the resonant cavity caused by the mis-adjustment of cavity mirrors. These results are useful for improving the design of optical parametric oscillator system and increasing its output energy.