低阈值高效率中红外可调谐连续波PPMgLN光学参量振荡器

摘要

报道了一种基于周期性极化晶体PPMgLN、连续波、线性外腔结构、宽带可调谐单谐振光学参量振荡器.泵浦源采用LDA端面泵浦的Nd:YVO4连续波1.064 μm激光器,并通过优化泵浦光与信号光的模式匹配,获得了低阈值、高效率的中红外激光输出.光参量振荡阈值仅为1.09 W,是目前采用外腔结构所报道的最低值.在泵浦功率4.55 W时,可以获得最大功率为346.8 mW、波长为3.202 μm激光输出,中红外光的光光转化效率达到了7.6%.并通过改变PPMgLN晶体的极化周期,可以实现中红外2.98～4.19 μm宽带可调谐激光输出.此中红外激光器结构简单紧凑,可以室温运行.%We report a linear extra-cavity, tunable mid-infrared, Continuous Wave (CW) singly resonant Optical Parametric Oscillator (OPO) based on periodically poled MgO-doped LiNbO3 (PPMgLN). A Nd:YVO4 laser pumped by 808 nm LDA is used as the pump source. The threshold of OPO system is only 1.09 W at l 064 nm. A maximum idle laser output power of 346.8 mW at 3.202 μm has been achieved when the pump power is 4.55 W and it corresponds to an (only idler) optic-optic conversion efficiency of 7.6％. By shifting the PPMgLN crystal, the periods of the domain structure on the PPMgLN wafer can be changed, thus enabling a mid-infrared spectral widely tuning range of the laser output from 2.98～4.19 μm. This laser is very compact, simple and operated at room temperature.