报道了一台高单脉冲能量的光参量振荡(OPO)2 μm固体激光器。采用电光调Q, Nd:YAG激光器输出的1064 nm激光, 抽运腔内两块光轴方向相向放置的KTP晶体, 通过双谐振光参量振荡(DROPO)技术获得2 μm激光输出。OPO谐振腔由2 μm反射镜、两块走离补偿的KTP晶体和2 μm输出镜组成。KTP晶体尺寸为8 mm×8 mm×15 mm, 切割角θ=53°, φ=0°。OPO采用Ⅱ类相位匹配(o→o+e)。当激光二极管单脉冲能量为1.02 J, 电光Q开关频率为30 Hz时, 获得了单脉冲能量107 mJ的简并波长2.1 μm激光输出, 808 nm激光二极管到2.1 μm光光转换效率为10.5 %, 光束质量因子分别为M2x=2.38, M2y=1.56。

A high energy optical parametric oscillated (OPO) 2 μm pulsed solid-state laser is demonstrated. The 2 μm laser is generated through a doubly resonant intracavity KTP OPO pumped by an electro-optic (EO) Q-switched Nd:YAG laser. The OPO resonator is composed of a 2 μm high reflection mirror, two walk-off compensated KTP crystals and a 2 μm output mirror. OPO is realized by the typeⅡ phase matching(o→o+e). Both KTP crystals are cut as θ=53°, φ=0°, and have a volume of 8 mm×8 mm×15 mm. When the energy of the diode laser is 1.02 J and the repetition rate of the EO Q-switch is 30 Hz, the highest single pulsed energy of the 2.1 μm laser is 107 mJ, and the conversion efficiency from 808 nm to 2.1 μm is 10.5%. The beam quality M2 factor is M2x=2.38, M2y=1.56, respectively.