Research progress of far-infrared solid-state lasers

The wavelength range of 8 - 12 mu m 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 mu m 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 mu m 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 mu m 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 mu m 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.