Resonant sum and difference frequency mixing in Hg

Abstract

Coherent tunable VUV radiation of narrow spectral width is generated by two-photon resonant sum and difference frequency mixing (\omega_{vuv}^{\pm} = 2\omega_{uv} \pm \omega_{D}) of pulsed dye laser radiation in Hg vapor. The UV frequency ω uv is tuned to the two-photon resonances 61S 0 - 71S 0 ( \lambda_{uv} = 3127.6 A), 61S 0 -61D 2 ( \lambda_{uv} = 2802.9 A), and 61S 0 - 71D 2 ( \lambda_{uv} = 2594.5 A). A second dye laser produces tunable radiation at ω D ( \lambda_{D} = 4200-6700 A). At input powers of 1-2 MW, the different conversion schemes generate VUV light pulses of typically 0.5-3 kW in spectral regions between 1090 and 1960 A. The experimental results provide information on the wavelength dependence of the generated VUV output, on the conversion efficiency, the phase-matching conditions, and on conversion limiting saturation phenomena. Besides the resonant frequency conversion, nonresonant frequency tripling and mixing is investigated at \lambda_{vuv} = 1800-1880 A in the vicinity of the resonance transition 61S 0 -61P 1 ( \lambda = 1849.5 A).