Efficient generation of tunable femtosecond pulses in the blue is reported in the nonlinear crystal BiB3O6. By use of fundamental pulses from a mode-locked Ti:sapphire laser at 76 MHz, single-pass second-harmonic average powers of as much as 830 mW have been generated at 50% conversion efficiency, and a tunable range of 375–435 nm in the blue is demonstrated. Temporal measurements using cross correlation of the fundamental and second-harmonic pulses in a 100-μm-thick β-BaB2O4 crystal result in blue pulse durations of 220 fs for 130-fs fundamental pulses. Direct experimental comparison with β-BaB2O4 confirms the superior performance BiB3O6 for second-harmonic generation of femtosecond pulses
