Diode laser pumped blue-light source based on intracavity sum frequency generation

Sum frequency mixing in KTiOPO4 of the 809 nm light from a GaAlAs laser diode and the 1064 nm light from a diode-pumped Nd laser has been used to generate blue radiation at 459 nm. The specific problems associated with the use of high-power multimode GaAlAs diode lasers as the source of the 809 nm mixing radiation were investigated in detail. Rapid modulation of the blue output and generation of 5 ns pulses by direct modulation of the GaAlAs laser diode were demonstrated.