1??W of blue 465-nm radiation generated by frequency doubling of the output of a high-power diode laser in critically phase-matched LiB_3O_5

Blue 465-nm radiation is generated by frequency doubling of the output of an InGaAs diode-laser oscillator–amplifier system in critically phase-matched ${\mathrm{LiB}}_3{\mathrm{O}}_5$ (LBO). The diode-laser system emitted 4 W of single-frequency 930-nm radiation in a near-diffraction-limited beam $\left(M^2<1.2\right)$. 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 $M^2$ beam parameter is less than 1.2.