Generation of high-brightness coherent radiation in the vacuum ultraviolet by four-wave parametric oscillation in mercury vapor

Abstract

Coherent radiation at several wavelengths in the vacuum ultraviolet (VUV) has been generated by four-wave parametric oscillation in mercury vapor. When a powerful ultraviolet pump laser of frequency ωp is tuned to a two-photon resonance, VUV signal photons at frequency ωs, as well as idler photons at frequency ωi, are generated such that ωs + ωi = 2ωp. A frequency-doubled dye laser tuned to two-photon resonance with the 6s6d1D2 level near 280.3 nm produced output at 184.9 and 143.5 nm. A tunable krypton fluoride excimer laser tuned to two-photon resonance with the 6s10s1S0 level near 248.7 nm produced output at 140.1, 130.7, 130.1, 125.9, and 125.0 nm. Approximately 1-μJ, 200-W pulses were observed at 143.5 and 125.9 nm.