基于中红外光参量振荡器光束质量优化的90°像旋转四镜非平面环形谐振腔型设计与分析

为改善中红外光参量振荡器(OPO)激光输出光束质量,设计了一种90°像旋转四镜非平面环形腔型结构.通过建立单位球等效计算方法,对此种特殊腔型结构存在的像旋转角进行计算,并由此确定了适用于中红外OPO运行的90°像旋转谐振腔结构相关参数.在此基础上进一步建立了非对称轴环形腔中光场模式自再现模型,分析得出随着像旋转角由0°向90°变化,谐振腔内光场模式逐渐均匀化,当旋转角为90°时,基模以及高阶模都表现出非常好的中心对称性.基于此采用中红外ZnGeP_2 OPO对所设计的腔型参数进行实验测量,实现了光束质量M_X~2=1.81和M_Y~2=1.61.由此可以证明所设计的90°像旋转四镜非平面环形腔对中红外OPO激光系统的输出光束质量的优化有显著效果.     

A Stable Wavelength Operation Ho:YAG Laser with Orthogonally Polarized Pump

A stable wavelength operation Ho:YAG laser dual-pumped by two orthogonally polarized Tm:YLF lasers is reported. Under the cw operation mode, a laser output power of 24 W is measured. The corresponding opticaloptical conversion efficiency is 44.75% and the slope efficiency is 50.12%. Under the Q-switched operation mode,the output maximum average power is 22.8 W at the re-frequency of 6 kHz. The corresponding optical-optical conversion efficiency and slope efficiency are 42.64% and 48.01%, respectively. The output central wavelength is 2090.73 nm, the linewidth is 0.40 nm, and the beam quality is M~2 1.6. Moreover, the shift of the output central wavelength is less than 0.01 nm, and the linewidth shift is also less than 0.01 nm.