Efficient frequency tripling of ArF laser in a hydrogen gas jet

Abstract

Higher harmonic generation in the extreme-ultraviolet (XUV) region is also demonstrated in rare gas jets, but the conversion efficiency is poor. High-brightness coherent source with high repetition rate has not ever been developed in XUV region. We found that the efficient third-harmonic generation (THG) of an ArF laser was obtained by the resonant enhancement of χ3 when the laser was tuned at one of the two-photon resonant lines of hydrogen molecules.1-3 Using this scheme, we can build up a 64.4-nm XUV coherent source with high average power. This light source will be useful for practical applications such as optical processing, because the coversion scheme is very simple.