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