All-solid-state laser has high efficiency, long service life and small volume, and is relatively easier to produce laser with high power and high beam quality. These advantages makes all-solid-state laser being widely used in coherent optical detection, advanced manufacturing, environment monitoring, material processing and handling, high density storage, optical communication, biological detection, etc.

Since the advent of ultraviolet laser at the end of the 20th century, scientists have carried out in-depth and extensive research on it by using different combination of gain medium, laser cavity type and pumping mode. The first 213nm laser was produced by pumping gain medium CaF₂: U³⁺ with laser diode. Then people used KN crystal to obtain 213nm continuous UV light of 2.1W. In 2000, Japanese researchers made a breakthrough in the acousto-optic Q-switched Nd:YAG 1064nm laser by using improved high-quality CLBO crystal, acquired 20W output of 266nm UV pulse. With the improvement of processing technology of optical components, the UV band gradually broke the limit of 355nm, 266nm and 213nm. In 2006, 20mW 236nm laser was obtained by quadrupling the frequency of a passively Q-switched quasi-three-level 946nm laser using PPKTP (periodically polarized KTP) crystals and BBO crystals. In 2008, a quasi-three-level Nd:YAG active Q-switched laser was reported which can output 237nm laser with pulse width of 1.9ns and average power of 7.6mW. In 2014, On this basis, researchers further optimized the aligning three-level Nd:YAG active Q-switched laser and obtained 600mW 237nm laser output, which is the highest average power so fa at 236nm UV wavelength.