8~12 μm波段是大气的一个窗口, 被定义为长波红外波段。该波段激光对雾、烟尘等具有较强的穿透力, 在激光光电对抗、激光遥感、医疗、环境监测及光通讯领域具有重要的应用前景。本文调研了常用的8~12 μm非线性频率变换晶体, 以及基于非线性频率变换晶体的远红外光参量振荡器的研究进展, 对国内外能实现8~12 μm波段激光输出的非线性晶体及激光系统进行了系统地归纳和总结, 通过分析比较得出在8~12 μm波段获得的最大输出能量为毫焦量级, 最大功率为瓦量级。国内该技术与国外有着不小的差距, 主要受制于高重频、高功率脉冲1~3 μm泵浦源技术不成熟及高性能非线性晶体材料研制基础薄弱, 我国在长波远红外固体激光器领域研究进展缓慢, 因此研制大尺寸、高质量远红外激光晶体及输出波长更长的远红外高功率激光器已经成为激光器未来发展方向之一。

The wavelength range of 8-12 μm is defined as the long-wave infrared band, which opens a window for atmospheric transmission. The laser band has strong penetrating power for fog, smoke etc., and has important application prospects in the fields of laser photoelectric countermeasures, laser remote sensing, medical treatment, environmental monitoring and optical communication. In this paper, the commonly used 8-12 μm nonlinear frequency conversion crystal, and the research progress of far-infrared optical parametric oscillator based on nonlinear frequency conversion crystal are investigated. The nonlinear crystal and laser system which can realize the laser output of 8-12 μm band at home and abroad are systematically summarize. Through analysis and comparison, it is concluded that the maximum output energy obtained in the 8-12 μm band is in the order of mJ and the maximum power is in the order of W. However, the technology in China is currently lagging behind in the world. The main reason is that the high-frequency, high-power pulse 1-3 μm pump source technology is immature and the development of high-performance nonlinear crystal materials is weak. Due to the slow research progress in the field of long-wave far-infrared solid-state lasers in China, the development of large-size, high-quality far-infrared laser crystals and far-infrared high-power lasers with longer output wavelengths has become one of the future development directions.