高功率中红外3.8μm激光器

High-power mid-infrared 3.8 μm laser

采用1.06μm激光泵浦准相位匹配周期极化铌酸锂(PPMgLN)晶体光参量振荡器,实现高功率高效率高重复频率3.84μm中红外激光输出。泵浦源为椭圆光斑1.06μm激光,PPMgLN晶体MgO摩尔分数为5%,光参量振荡器为外腔单谐振结构,采用e→e+e相位匹配,利用了PPMgLN晶体的最大非线性系数。在1.06μm激光功率为73 W,声光Q开关工作频率为7.5 kHz的条件下,获得平均功率8.3 W,波长3.84μm激光输出,光-光转换斜率效率14.1%,水平和垂直方向光束质量平方因子分别为1.94,4.57。

A high-average-power high-efficiency high-repetition-rate mid-infrared laser at 3.84 μm was demonstrated. The laser was based on quasi-phase-matched periodically poled LiNbO3 （PPMgLN） optical parametric oscillator（OPO）, pumped by elliptical 1.06 μm laser beam. The PPMgLN crystal was 5 % MgO-doped. The OPO was extra-cavity and single-resonated OPO. The pump beam polarization matched e→e＋e interaction in PPMgLN, thus maximal nonlinear coefficient was effective. When pump power was 73 W at acoustic-optic Q-switch repetition rate 7. S kHz, 8.3 W average output power at 3.84 μm was obtained with slope efficiency 14.1%. The optical beam quality factors were 1.94,4.57 in horizontal and perpendicular direction, respectively.