Efficient generation at 421 nm by resonantly enhanced doubling of GaAlAs laser diode array emission

Abstract

The 842-nm diffraction-limited emission from an injection-locked laser diode array was frequency doubled using a monolithic spherical-mirror KNbO3 crystal cavity. Maximum unidirectional external 421 nm power of 24 mW was generated with 167 mW of pump power. Maximum total internal second-harmonic power and conversion efficiency of 64 mW and 45% were obtained. Effects of heating in the crystal are described.