Blue 459-nm laser source with rapid modulation based on intracavity frequency mixing

Noncritically phase-matched sum frequency mixing in potassium titanyl phosphate (KTP) of 1064- and 809-nm radiation to produce blue light at 459 nm was recently reported and shown to have large angular tolerances and an extremely wide temperature tolerance. For a practical compact source, it is desirable to provide the pump radiation from a GaAlAs laser diode. The availability of high-power laser diodes at wavelengths around 809 nm makes a laser-diode-pumped blue laser employing the frequency mixing technique possible, and high-speed modulation of the blue radiation is possible by direct modulation of the laser diode injection current. The use of GaAlAs lase diodes for the generation of 459-nm radiation based on the mixing process described here has been demonstrated, and detailed results are reported