Noncritical phase-matching characteristics of 248 nm deep-UV generation in DKDP crystals

KDP-family crystals with large-diameter growth characteristics are ideal materials for obtaining high-energy deep-UV lasers. Based on the third-harmonic generation of 1064 nm laser and the 827 nm optical parametric oscillation pumped by 532 nm radiation, 248 nm deep-UV laser radiations were obtained via noncritical phase-matching (NCPM) sum-frequency generation in 89.6% and 98.8% DKDP crystals at 112.4 and 93.6 °C, respectively. The NCPM characteristics of the DKDP crystals were presented by tuning the crystal temperatures and incident angles, which was conducive to further exploiting the advantages of NCPM. This work presents a feasible high-energy 248 nm generation scheme to serve as the seed for the KrF excimer laser amplifier and pave the way for the energy improvement and applications of the deep-UV radiation by fully utilizing the large-diameter advantages of KDP-family crystals.