Picosecond high-power 213-nm deep-ultraviolet laser generation using ß-BaB2O4 crystal

In this study, we successfully demonstrate the achievement of 1.37 W average power for a picosecond deep ultraviolet (DUV) laser at 213 nm with a 1 MHz repetition rate using beta-BaB2O4 (BBO) crystals, which is the highest output power of a 213 nm picosecond laser system with an all-solid-state setup so far. The laser system generates over 1.3 mu J 213-nm pulse energy. The fifth harmonic is generated by sum-frequency generation of the 532 and 355 nm beams based on a "2 + 3" scheme. BBO crystals with lengths of 6, 8, and 10 mm are investigated. Furthermore, the DUV laser system produces a high-beam quality and narrow linewidth output. The DUV system can be stably maintained over 100 h with expanded beam sizes of 532 and 355 nm at 800 mW, and without requiring a change in the positions and temperatures of nonlinear crystals.