3.6 mW blue light by direct frequency doubling of a diode laser using an aperiodically poled lithium niobate crystal

3.6 mW blue (490 nm) light has been generated from a frequency-doubled, gain-switched InGaAs/GaAs diode laser using an aperiodically poled lithium niobate crystal. The matching of the crystal acceptance bandwidth to the laser spectral profile resulted in significant improvements to the conversion efficiency.