摘要 |
A method and apparatus are provided for delivering a laser beam from a laser, such as an F2 laser, to a target through a sealed enclosure. The enclosure is evacuated and back-filled with an inert gas repeatedly for a number of times sufficient to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter, an inert gas flow is established and maintained within the enclosure during operation of the laser. Propagation with significant transmittance of a sub-200 nm beam through the enclosure is particularly enabled.
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