报道了一台高功率中红外激光器。通过理论计算,得到了光参量振荡器输出波长随MgO:PPLN晶体温度变化的调谐曲线,分析了晶体热膨胀对输出波长的影响;通过声光调Q,Nd:YAG激光器输出的1064 nm激光作为抽运光,抽运掺氧化镁的周期性极化铌酸锂晶体(MgO:PPLN),利用光参量振荡(OPO)技术实现了1.75 μm和中红外2.71 μm激光输出。当重复频率为7 kHz,抽运光功率为104 W时,总的平均输出功率为53.2 W,转换效率为51%。从转换曲线上看,并没有达到饱和区域,因此在晶体损伤阈值以下,增加抽运光功率,OPO的输出功率将会有所提高。

A high-power mid-infrared laser is presented. The temperature-dependent tuning curve of the output wavelength of OPO is obtained through theoretical calculation,and the wavelength change with the effect of the crystal′s heat expansion is analyzed. The MgO doped periodically poled lithium niobate (MgO:PPLN) is pumped by an acoustic-optical Q-switched Nd:YAG laser. Using the optical parametric oscillator (OPO) configuration,an average power of 53.2 W for both 1.75 μm and 2.71 μm laser is obtained when the pump power is 104 W,at the repetition rate of 7 kHz,the conversion efficiency is 51%. The conversion curve doesn′t reach the saturated area,so the output power should increase with a higher pump power under the damage threshold of the crystal.