Generation and amplification of ultrashort UV pulses via parametric four-wave interactions in transparent solid-state media

Abstract

We report on efficient generation of the ultrashort ultraviolet light pulses by means of phase-matched four-wave optical parametric amplification and four-wave difference frequency mixing in UV-transparent solids with cubic nonlinearity. Broadband four-wave optical parametric amplification around 330 nm is investigated theoretically and demonstrated experimentally in optically isotropic materials, such as fused silica and CaF₂ crystals. The results suggest that powerful broadband ultraviolet pulses as short as 7.5 fs (in the transform limit) could be amplied in the field of milijoule 1-ps visible pulses. Efficient generation of 1-ps pulses at the 3rd (351 nm), 5th (211 nm), and, in particular, 6th (176 nm) harmonics of the Nd:glass laser is experimentally demonstrated through non-collinearly phase-matched four-wave difference-frequency mixing in fused silica, CaF₂ and MgF₂ crystals.
Keywords: four-wave mixing, optical parametric amplification
PACS: 42.65.Jx, 42.25.Tg, 42.65.Yj, 42.65.Hw