Continuous-wave ultraviolet generation at 354nm in a periodically poled MgO:LiNbO3 by frequency tripling of a diode end-pumped Nd:GdVO4 microlaser

Abstract

Continuous-wave UV radiation at 354nm, the third harmonic of a Nd:GdVO4 laser operating at 1063nm, is reported from single-pass cascaded, first-order periodically poled MgO:LiNbO3 (PPMgLN) crystals. A high-voltage multipulse poling method was used in order to realize PPMgLN with uniform domain period (Λ) of micron-order width and 50% duty cycle along the entire crystal length. Initially, second-harmonic generation of the 1063nm Nd:GdVO4 laser at 2.1%∕W conversion efficiency, producing 1.15W at 531nm, is obtained from a 10-mm-long PPMgLN with Λ=6.95μm. Sum frequency mixing of this 531nm light with the residual 1063nm fundamental radiation in a 3.6-mm-long PPMgLN with Λ=1.78μm produces 47mW of UV with 3.9%∕W∕cm normalized conversion efficiency.