报道了一台高重复频率高效率2 μm激光器。理论计算了1.064 μm激光抽运Ⅱ类相位匹配KTP晶体的角度调谐曲线,得出KTP晶体按φ=0°,θ=54°切割可获得近简并波长的2 μm激光输出。使用1.064 μm Nd∶YAG模块作为抽运源,抽运内腔式双晶体走离补偿双谐振光参量振荡器(DROPO),在7 kHz声光调Q频率下,获得23.6 W 的2.12 μm激光输出,808 nm激光二极管(LD)出光获得2 μm激光的斜率效率超过19%。

A high-repetition-rate high-efficiency 2 μm laser was demonstrated. The tuning curve of the type Ⅱ phase matching KTP crystal pumped by 1.064 μm laser was calculated and it shows that when cut at φ=0°, θ=54°, a KTP optical parametric oscillator (OPO) gets output at near degenerated wavelength at 2 μm. The pump source was 1.064 μm Nd∶YAG module. Walk-off compensation was realized by two short crystals in intracavity doubly resonant optical parametric oscillator (DROPO) and the average power of 23.6 W at 2.12 μm is obtained. The pulse repetition frequency of acoustic-optic Q-switch was 7 kHz and the slope efficiency of 808 nm laser diode (LD) to 2 μm laser was higher than 19%.