Picosecond high-power 355-nm UV generation in CsLiB₆O₁₀ crystal

We report third-harmonic generation (THG) at 355 nm in CsLiB₆O₁₀ (CLBO) by using sum-frequency mixing process. As a fundamental laser source, we employ a hybrid master oscillator power amplifier (MOPA) system seeded by a gain-switched laser diode (GS-LD) at 1064 nm to produce narrow spectral picosecond pulses. Both CLBO and walk-off compensated prism-coupled CLBO device generate over 30-W output of 355-nm UV lights, which means walk-off effect in CLBO is negligible in the picosecond laser system. The maximum THG conversion efficiency from the fundamental reaches about 48%, which is 1.2 times higher than that of LiB₃O₅ (LBO). Theoretical THG outputs with CLBO and LBO are numerically calculated in order to verify the validity of these experimental results in detail.