Femtosecond ultraviolet pulse generation in β-BaB2O4

Abstract
Intracavity doubling in β‐BaB2 O4 (BBO) of femtosecond pulses into the ultraviolet with high efficiency is reported. Pulse widths down to 43 fs at a 108 Hz repetition rate and outputs as high as 20 mW per arm of the femtosecond laser on a continuous‐wave basis can be achieved. The ultraviolet pulse widths were determined through detailed cross‐correlation measurements based on sum‐frequency mixing to 210 nm in ultrathin BBO crystals.