2 μm、中波红外3~5 μm及长波红外8~12 μm波段的激光处于大气传输窗口，在激光医疗、环境监测、激光雷达、化学遥感和红外对抗等领域有着非常广阔的应用前景。基于非线性频率转换技术，采用非线性光学晶体在实现中长波红外固体激光输出方面具有结构简单、宽调谐和高功率等技术优势。尤其是使用2 μm单掺Ho固体激光器泵浦ZnGeP₂晶体，在3~5 μm和8~10 μm中长波红外输出中性能优异。在平均输出功率方面，目前可达到102 W@3~5 μm、12.6 W@8.2 μm以及3.5 W@9.8 μm的输出水平，光束质量M²均小于3，其中中波的光光转换效率可达60%。文中针对2 μm单掺Ho固体激光器及ZnGeP₂晶体在中长波输出方面进行了总结。

2 μm, 3-5 μm and 8-12 μm infrared lasers are located in the atmospheric transmission window, which have broad applications in laser medicine, laser imaging, environmental monitoring, lidar, chemical remote sensing and infrared countermeasure. Based on the optical nonlinear frequency conversion technology and nonlinear optical crystals, it has obvious advantages in achieving middle-long-wave infrared solid lasers, such as compact and simple structure, wide tunable wavelength range and high output power. Using ZnGeP₂ crystal with 2 μm Ho single-doped solid laser as pump especially has an outstanding performance in middle-long-wave infrared field. In the aspect of average output power, it has reached the level of 102 W@3-5 μm, 12.6 W@8.2 μm and 3.5 W@9.8 μm. Moreover, they all have a beam quality factor M² less than 3 and the corresponding optical-to-optical conversion efficiency of 3-5 μm is about 60%. This paper reviewed the research progress of 2 μm Ho single-doped solid laser and application of ZnGeP₂ on middle-long-wave infrared in detail.