High-power 390-nm laser source based on efficient frequency doubling of a tapered diode laser in an external resonant cavity

We frequency doubled the single-frequency beam from an external-cavity tapered laser diode operating at 780 nm in a resonant cavity containing a beta-barium berate crystal to generate an output at 390 nm with high efficiency. Output powers as great as 233 mW were obtained, corresponding to an efficiency of 65%/W. The resonant-cavity design was a low-loss three-mirror configuration that provided compensation for astigmatism and coma. The laser diode frequency was locked to the doubling-cavity resonance by use of the Hansch/Couillaud discrimination technique. (C) 1999 Optical Society of America.