External power-enhancement cavity versus intracavity frequency doubling of Ti:sapphire lasers using BIBO.

We report on continuous-wave second harmonic generation of near infrared Ti:sapphire lasers using room temperature critically phase-matched, angle-tuned BIBO (bismuth triborate, BiB(3)O(6)) crystals, placed both in an external power enhancement cavity and inside the laser resonator. In the first case we generate 70 mW of single-frequency radiation at 423 nm for 330 mW of input power at 846 nm. For intracavity frequency doubling we achieve 690 mW at 423 nm for 7.3 Watts of the Ti:sapphire laser pump power at 532 nm, representing a conversion efficiency of 9.5% from 532 to 423 nm. These tunable blue-violet systems are particularly attractive for laser cooling and trapping of alkaline-Earth atoms.