Ultraviolet laser is widely used in fluorescence detection, fine processing and lithography due to its high single photon energy and small diffraction effect. At present, in the field of industrial and scientific research, the method of obtaining ultraviolet laser is mainly divided into gas ultraviolet Lasers and solid-state lasers. Gas ultraviolet lasers include excimer lasers, hydrogen ion lasers, and nitrogen molecular lasers. However, gas lasers have been replaced by solid-state ultraviolet lasers pumped by laser diodes (LD) because of their large size, short life, and long-term maintenance. The most straightforward method for obtaining an all-solid-state UV laser is to perform intracavity or extracavity frequency conversion on the near-infrared wave of an erbium-doped solid-state laser to generate three or fourth harmonics. High-power end-pump UV lasers use Nd:YVO4 as a laser crystal, which is characterized by higher repetition frequency but lower peak power. In order to obtain h...
