提出了一种基于1064 nm掺镱光纤激光器泵浦MgO:PPLN的3.83 μm中红外光学参量振荡器。基于单谐振光学参量振荡器的阈值理论和线宽压窄前后的光束能量集中性理论，分析了不同泵浦光束聚焦深度下，谐振腔内光束分布情况以及线宽调制前后能量的不同集中程度对阈值和光-光转换效率所产生的影响。通过采用单个光纤布拉格光栅的方式压窄了泵浦光线宽，对比分析了在不同占空比下，泵浦光线宽压窄前后对中红外光学参量振荡器输出特性的影响。当泵浦功率为18 W，脉冲激光占空比为0.2%，脉宽为100 ns，泵浦光线宽为2.5 nm时，MgO:PPLN中红外光学参量振荡器获得功率为1.42 W的3.83 μm激光输出，光-光转换效率为7.9%。将线宽压窄到0.1 nm后，脉宽为2 ns，MgO:PPLN中红外光学参量振荡器获得最高功率为1.98 W的3.83 μm激光输出，光-光转换效率为11%，光束质量M²=1.89；同时相比于线宽压窄前激光输出效率提高了39.2%。

A continuous-wave (CW) π-polarized 1084 nm laser based on Nd:MgO:LiNbO3 under 888 nm thermally boosted pumping is reported. According to the absorption spectrum and energy level structure of Nd:MgO:LiNbO3, the 888 nm laser diode (LD) is used for thermally boosted pumping. This pumping method eliminates the quantum defect caused by the nonradiative transition in Nd:MgO:LiNbO3 under the traditional 813 nm pumping and effectively improves the serious thermal effect of the crystal. The unmatched polarized 1093 nm laser is completely suppressed, and the π-polarized laser output of 1084 nm in the whole pump range is realized by the 888 nm thermally boosted pumping. In the present work, we achieved the CW π-polarized 1084 nm laser with a maximum output power of 7.53 W and a slope efficiency of about 46.1%.

为了研究毫秒-纳秒组合脉冲激光辐照熔石英的温度场和应力场特征，基于热传导理论和弹塑性力学理论建立了二维轴对称几何模型，利用有限元分析软件对毫秒-纳秒组合脉冲激光辐照熔石英的过程进行了数值分析，得到了熔石英表面及内部的瞬态温度场和应力场的时空分布与变化规律。结果表明：组合脉冲激光中，毫秒激光脉宽为1 ms、能量为120 J，纳秒激光脉宽为10 ns、能量为80 mJ，Δt=1.0 ms条件下毫秒-纳秒组合脉冲激光辐照熔石英出现温度最佳延时。观察总能量相同的组合脉冲激光与毫秒脉冲激光致熔石英的热损伤结果，得到最佳能量配比。研究结果表明，组合脉冲激光中，毫秒脉冲激光对熔石英产生热效应，纳秒脉冲激光对熔石英产生应力效应。

为了研究硅基QPD在不同能量密度、不同脉宽激光辐照下的损伤面积、形貌，基于二维显微测量技术，测量了硅基QPD单一象限的损伤面积、形貌随激光能量密度和脉宽的变化。结果表明，在毫秒脉冲激光作用下，硅基QPD产生表面剥落、褶皱、裂纹、熔坑等损伤效果，且主要受入射激光功率密度影响，损伤面积随激光能量密度逐渐增加，随脉宽增加逐渐降低。通过实测分析，得出了不同激光脉宽下，硅基QPD表面形貌损伤阈值。激光脉宽为0.5 ms，能量密度为15.79 J/cm²时，硅基QPD出现熔融损伤；而脉宽为1.0、1.5、2.0、3.0 ms时，硅基QPD出现表面剥落的能量密度值为14.12、33.94、39.76、47.62 J/cm²。

We examined a 1514 nm eye-safe passively Q-switched self-optical parametric oscillator. The nonlinear crystal is an a-cut Nd:MgO:PPLN crystal, and the size of the crystal was 6 mm × 2 mm × 30 mm with 0.4 at.% Nd³⁺ doped and a grating period of 29.8 μm. When the crystal absorbed 12.8 W, the output maximum single-pulse energy reached 39 μJ, and a pulse width of 6.1 ns at a repetition rate of 5.4 kHz was obtained. The peak power was 6 kW, giving a slope efficiency of 42%.