3.0 W blue light generation by frequency doubling of broad area semiconductor amplifier emission

Broad area GaAlAs amplifier emission is frequency doubled in a single pass through a 2 cm long KNbO3 crystal. A maximum peak power of 3.0 W at 432 nm is achieved with 15.6 W of incident fundamental power and 0.3 μs long pulses, corresponding to a 190% nonlinear conversion efficiency.