title: Continuous-wave, single-pass, single-frequency second-harmonic-generation at 266 nm based on birefringent-multicrystal scheme.
abstract: We report the implementation of a compact cascaded multicrystal scheme based on birefringent crystals in critical phase-matching, for the generation of continuous-wave (cw) radiation in the deep ultraviolet (UV). The approach comprises a cascade of 4 single-pass second-harmonic-generation (SHG) stages in β-BaB2O4(BBO) pumped by a single-frequency cw green source at 532 nm. A deep-UV cw output power of 37.7 mW at 266 nm has been obtained with a high passive power stability of 0.12% rms over more than 4 hours. Characterization and optimization of the system in each stage has been systematically performed. Angular phase-matching acceptance bandwidth under tight focusing in BBO, and spectral properties of the deep-UV radiation, have been studied. Theoretical calculations for SHG in the cascaded scheme based on birefringent phase-matching have been performed, and enhancement in UV power compared to single-stage single-pass scheme are studied. Theoretical comparison of BBO with other potential crystals for deep-UV generation in cascaded multicrystal scheme is also presented.
authors.forename: Kavita
authors.initials: K
authors.lastname: Devi
authors.forename: S
authors.initials: S
authors.lastname: Parsa
authors.forename: M
authors.initials: M
authors.lastname: Ebrahim-Zadeh