| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum ultraviolet laser capable of preventing the damping of a beam of oscillated laser and contamination on optical components within an optical path. SOLUTION: A vacuum ultraviolet laser 1 comprises optical path covers 13, 14 and 22 for covering a space of optical path 21 through which a laser beam 11 passes, O-ring grooves 24 provided for the covers 13, 14 and 22, respectively, and O-rings 25 inserted into the grooves 24, respectively, whereby the laser beam 11 in a vacuum ultraviolet region is oscillated. In such laser 1, a trap accommodating section 41 is arranged at a location closer to the outside air than each groove 24 to accommodate, within the section 41, an impurity trap 42 for removing impurities in the air. Further, purging means for purging an inert gas onto the space 21 is provided, and a trap device 47 for removing impurities from the purged inert gas is also arranged along a purging pipe 30.
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