| 摘要 |
An efficient F2 laser is provided with improvements in line selection, monitoring capabilities, alignment stabilization, performance at high repetition rates and polarization characteristics. Line selection is preferably provided by a transmission grating or a grism. The grating or grism preferably outcouples the laser beam. The line selection may be fully provided at the front optics module. A monitor grating and an array detector monitor the intensity of the selected (and unselected) lines for line selection control. An energy detector is enclosed in an inert gas purged environment at slight overpressure. A blue or green reference beam is used for F2 laser beam alignment stabilization and/or spectral monitoring of the output laser beam. The blue or green reference beam advantageously is not reflected out with a atomic fluorine red emission of the laser and is easily resolved from the red emission. The clearing ratio of the laser gas flow through the discharge area is reduced by narrowing the discharge width using improved laser electrodes and/or by increasing the gas flow rate through the discharge while maintaining uniformity by using a more aerodynamic discharge chamber. The F2 laser beam is substantially polarized, e.g., 98% or better, using at least one intracavity polarization element preferably in combination with Brewster discharge chamber windows.
|
