Schellhorn Martin, Spindler Gerhard, Eichhorn Marc
Opt Lett. 2017 Mar 15;42(6):1185-1188. doi: 10.1364/OL.42.001185.
The beam quality of a high-energy mid-infrared ZnGeP (ZGP) optical parametric oscillator has been improved by use of a negative lens inside the nonplanar fractional-image-rotation enhancement (FIRE) resonator compensating for the thermal lensing and gain guiding effects. With an f=-0.9 m CaF lens, the beam quality is 1.5 and ∼2 for the resonant signal beam and the non-resonant idler beam, respectively. Up to 33 mJ of mid-infrared pulse energy in the 3-5 μm wavelength range is obtained with 94 mJ of pump energy on the crystal. This is an improvement of the beam quality by a factor of 3 for the signal beam and ∼2 for the idler beam compared without using a lens inside the FIRE resonator.
通过在非平面分数图像旋转增强（FIRE）谐振腔内使用负透镜来补偿热透镜效应和增益引导效应，高能中红外ZnGeP（ZGP）光学参量振荡器的光束质量得到了改善。使用焦距f = -0.9 m的CaF透镜时，谐振信号光束和非谐振闲频光束的光束质量分别为1.5和2。在晶体上泵浦能量为94 mJ的情况下，在3-5μm波长范围内获得了高达33 mJ的中红外脉冲能量。与在FIRE谐振腔内不使用透镜相比，信号光束的光束质量提高了3倍，闲频光束提高了2倍。
