| 摘要 |
PURPOSE:To prevent deterioration of an optical member and to maintain a laser output stable for a long period by so forming a gap between the end face of a nozzle and the inner surface of the member as to uniformly spray laser gas to be injected from the inlet hole of a pressure vessel to substantially all the area of the inner surface of the member. CONSTITUTION:Laser gas injected from an inlet hole 5 flows between a window holder 16 and a cylindrical nozzle 17, and then flows in a gap 18 between the end face of the nozzle 17 and the inner surfaces of transmitting windows 3, 4 of optical members. Then, while it flows through a laser light inlet 20 to the inside of the nozzle 17 to pass the gap 18, it is uniformly sprayed over substantially all the area of the inner surfaces of the windows 3, 4 to prevent dust from adhering to the windows 3, 4. Laser light is generated by discharge exciting, and the generated light can be emitted from the windows 3, 4. Thus, deterioration of the member is prevented to maintain the laser output stable for a long period. |
