11.8W高效率掺氧化镁的周期极化铌酸锂晶体光参量振荡2.7μm激光器

High Efficiency Periodically Poled Lithium Niobate with MgO Optical Parametric Oscillator 2.7 μm Laser with 11.8 W Output Power

报道了采用1064 nm激光椭圆光斑抽运掺氧化镁的周期极化铌酸锂(PPMgLN)晶体准相位匹配(QPM)技术实现2.7μm激光输出的实验结果,理论计算了PPMgLN晶体准相位匹配周期调谐曲线,得出PPMgLN晶体周期为31.3 μm时可获得中红外波长2.7μm激光输出。PPMgLN晶体(MgO掺杂摩尔分数为5%)单谐振光参量振荡(OPO)技术采用e→e+e相位匹配,消除了光束之间的走离效应和利用了PPMgLN晶体的最大非线性系数d_(33)(27.4 pm/V)。在1064 nm激光抽运功率78 W,卢光Q开关工作频率8 kHz的条件下,获得了平均功率11.8 W,波长2.72μm的激光输出,斜率效率19.5%,对应闲频波长1.75μm激光输出功率约24 W。2.7 μm激光水平方向和垂直方向光束质量M^2因子分别为2.04和5.56。

The experimental results of high-efficiency 2.7μm laser are demonstrated on quasi-phase-matched single-resonated optical parametric oscillator（OPO） in periodically poled lithium niobate with MgO（PPMgLN） pumped by 1064 nm laser of elliptical beam. Theoretical analyses of PPMgLN grating period tuning is presented. When grating period is 31.3 μm, a PPMgLN OPO could get output at wavelength of 2.7 vm. The pump beam polarization matches the e→e＋e interaction in PPMgLN （5 mol% MgO-doping）, thus maximal nonlinear coefficient d33 （27.4 pm/V） is effective and walk-off of beams can be avoided. When pump power was 78 W with 8 kHz Q-switch, an average output power of 11.8 W at 2.72 μm was obtained with slope efficiency of 19.5%, with 24 W at the corresponding idle wavelength of 1.75μm. The M^2 factor of 2. 7 μm laser was 2.04, 5.56 in parellel and perpendicular direction respectively.