Blue 465-nm radiation is generated by frequency doubling of the output of an InGaAs diode-laser oscillator–amplifier system in critically phase-matched LiB<sub>3</sub>O<sub>5</sub> (LBO). The diode-laser system emitted 4 W of single-frequency 930-nm radiation in a near-diffraction-limited beam (<i>M</i><sup>2</sup><1.2) . The laser power is enhanced to values of up to 150 W in a resonant external ring cavity. The LBO crystal is placed at a resonator internal focus. The frequency doubling in the LBO crystal generates blue radiation at 465 nm with a power of 1 W. The spectral width of the blue radiation is less than 3 MHz, and the value of the M<sup>2</sup> beam parameter is less than 1.2.
© 1999 Optical Society of America
(140.2020) Lasers and laser optics : Diode lasers
(140.3380) Lasers and laser optics : Laser materials
(140.3560) Lasers and laser optics : Lasers, ring
(190.2620) Nonlinear optics : Harmonic generation and mixing
D. Woll, B. Beier, K.-J. Boller, R. Wallenstein, M. Hagberg, and S. O’Brien, "1 W of blue 465-nm radiation generated by frequency doubling of the output of a high-power diode laser in critically phase-matched LiB3O5," Opt. Lett. 24, 691-693 (1999)