157 nm F2 Lasers.

Abstract

Current research activities on the electric discharge pumped molecular fluorine lasers at 157 nm, and the present understanding for the laser kinetics are reviewed. Fast and intense discharge excitation, which is more than one order of magnitude higher than excitation rates used for conventional rare-gas halide excimer lasers, improved both output laser energy (100-200 mJ) and efficiency (up to 0.4 %). Successful introduction of cryogenic gas purification that traps various impurity molecules introduced by gases supplied or by secondary reactions during the discharge extended the F2 laser gas lifetime to > 5×105 shots. Further development of high repetition rate high-power exciters, excellent optics with higher damage thresholds, and large aperture and well-controlled low divergence laser beams will open up various useful applications in photochemistry or photo ablation processes.