Two-photon-resonant difference-frequency generation using an ArF excimer laser provides widely tunable vacuum-ultraviolet (VUV) radiation at high pulse energies. Two-photon resonances in H<sub>2</sub>, Kr, and Hd are within the tuning range of the ArF laser. With this technique we have directly measured >65 μJ at 133 nm. H<sub>2</sub> has a significantly smaller phase mismatch than Kr, leading to more efficient VUV generation, particularly at shorter VUV wavelengths. However, mixing in H<sub>2</sub> also produces additional VUV lines from two-photon excited amplified spontaneous emission. We have observed new amplified spontaneous-emission lines produced in this manner. H<sub>2</sub> is ineffective at generation of Lyman-α radiation owing to the production of H atoms. With a phase-matched mixture of Kr and Ar, we have directly measured 7 μJ at Lyman-α. A physical basis for the asymmetric tuning profile in this gas mixture is presented. With light from this VUV source we have performed 1+1 resonantly enhanced multiphoton ionization in Xe at 147 nm and two-photon-excited fluorescence in Ne at 133 nm.
© 2000 Optical Society of America
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers
(190.1900) Nonlinear optics : Diagnostic applications of nonlinear optics
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(300.6410) Spectroscopy : Spectroscopy, multiphoton
Gregory W. Faris, Scott A. Meyer, Mark J. Dyer, and Michael J. Banks, "Two-photon-resonant difference-frequency mixing with an ArF excimer laser: vacuum-ultraviolet generation and multiphoton spectroscopy," J. Opt. Soc. Am. B 17, 1856-1866 (2000)