Second-harmonic generation at 421 nm using injection-locked GaAlAs laser array and KNbO3

Abstract

Significant improvement in frequency doubling efficiency of a cw output of a GaAlAs laser diode is described. Up to 0.72 mW of 421 nm power was generated by illuminating a KNbO3 crystal with a 270 mW diffraction-limited beam generated by an externally injection-locked laser diode array, operating in a single-mode and single-far-field lobe.