Ultraviolet laser resonant cavity, laser and laser processing device

The utility model provides an ultraviolet laser resonant cavity, a laser and a laser processing device, and relates to the technical field of laser. According to the first aspect, the ultraviolet laser resonant cavity comprises a starting point reflector, an end point reflector, a first relay reflector and a second relay reflector, light beams entering the resonant cavity go back and forth between the starting point reflector and the end point reflector, and the first relay reflector and the second relay reflector are arranged between the starting point reflector and the end point reflector. The first relay reflecting mirror is arranged on the optical axis between the starting point reflecting mirror and the ending point reflecting mirror, and a light beam propagating from the starting point reflecting mirror to the ending point reflecting mirror sequentially passes through the first relay reflecting mirror, the second relay reflecting mirror and the ending point reflecting mirror; the laser crystal, the ligh