| 摘要 |
A rare gas-halogen excimer laser in which the laser gases are exposed only to compatible materials that react with the laser gases to produce stable reaction products having a low vapor pressure, so as to reduce contamination of the gases and optics. High-purity nickel is the preferred material for components that are electrically conductive, and high-purity alumina is the preferred material for components that are non-electrically conductive. No non-compatible materials are used. In another feature, magnetic fluid seals are provided for the laser's fan-shaft, to isolate the shaft bearings and thereby isolate any non-compatible lubricant for the bearings. The fan uses magnetic coupling so that an isolating enclosure may be placed over the magnetic fluid seal to prevent the leakage of gases into the surrounding environment if the seal ever fails. In yet another feature of the invention, the excimer laser includes a window assembly that is movable and sized such that a succession of non-overlapping portions of it may be selectively fixed in the path of the exiting laser beam. An excimer laser that is both reliable, safe and long-lasting is thereby provided.
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