W级中红外宽调谐光学参量振荡器的研究

Watt-level,mid-infrared,wide-tunable optical parametric oscillator

报道了一个低阈值、宽调谐、中红外单谐振掺MgO的周期性极化LiNbO3(PPMgLN)晶体光学参量振荡器(OPO)。利用声光调Q的Nd:YVO4激光器作为泵浦源,采用外腔结构,在室温下实现了PPMgLN晶体的准相位匹配(QPM)OPO。OPO阈值仅为0.4 W(重复频率40 kHz,单脉冲能量10μJ,脉宽160 ns);在泵浦光为6.6W(重复频率40 kHz,脉冲能量165μJ,脉宽65 ns)、PPMgLN周期为30μm时,获得了1.13 W的3.61μm中红外脉冲激光输出,光-光转化效率达到17.1%,同时获得了880 mW的1.51μm信号光输出,并且通过改变晶体的周期,实现了闲频光3.13～4.19μm中红外宽带可调谐激光输出。重点讨论了闲频光的功率、调谐和脉冲特性以及功率稳定性问题。

A wide tunable,low threshold,and mid-infrared singly resonant optical parametric oscillator（OPO） is proposed based on periodically poled MgO：LiNbO3（PPMgLN）.An acousto-optic Q-switched Nd：YVO4 laser is used as the pump source and a Nd：YVO4/PPMgLN OPO is obtained.The threshold of OPO system is only 0.4 W（40 kHz,10 μJ,160 ns） at 1 064 nm.When the pump power is 6.6 W（165 μJ,65 ns）,a maximum idle laser output power is 1.13 W at 3.61 μm,which corresponds to an optic-optic conversion efficiency of 17.1%.Besides,a maximum signal laser output power of 880 mW at 1.51 μm has been achieved.By shifting the PPMgLN crystal,the periods of the domain structure on the PPMgLN wafer can be changed,which enables an idle spectral tuning range from 3.13-4.19 μm.And the power,pulse and tuning characteristics,as well as power stability of the idle laser are described.