Schellhorn Martin, Spindler Gerhard, Eichhorn Marc
Opt Express. 2018 Jan 22;26(2):1402-1410. doi: 10.1364/OE.26.001402.
Divergence compensation, optimization of the optical-to-optical efficiency, and high beam quality of signal and idler beams of a high-energy mid-infrared ZnGeP (ZGP) optical parametric oscillator (OPO) have been demonstrated by use of a Galilean telescope inside the nonplanar fractional-image-rotation enhancement (FIRE) ring resonator. With a small variation of the distance between the lenses of the telescope, the divergences of signal and idler beams could be adjusted. Up to 36 mJ of mid-infrared pulse energy in the 3-5 µm wavelength range is obtained with 92 mJ of pump energy on crystal. The beam quality factors M are < 1.5 for the resonant signal beam and the non-resonant idler beam, respectively. Actually, this is an improvement of the beam quality by a factor 3 for the signal and ~2.7 for the idler beam compared without using a telescope inside the FIRE ring resonator.
通过在非平面分数图像旋转增强（FIRE）环形谐振器内使用伽利略望远镜，实现了高能中红外ZnGeP（ZGP）光学参量振荡器（OPO）的发散补偿、光光效率优化以及信号光和闲频光的高光束质量。通过略微改变望远镜透镜之间的距离，可以调节信号光和闲频光的发散角。在晶体上泵浦能量为92 mJ时，在3 - 5 µm波长范围内可获得高达36 mJ的中红外脉冲能量。谐振信号光和非谐振闲频光的光束质量因子M分别小于1.5。实际上，与在FIRE环形谐振器内不使用望远镜相比，信号光的光束质量提高了3倍，闲频光提高了约2.7倍。
