High-efficiency direct-pumped Nd:YVO4-LBO laser operating at 671 nm

The continuous-wave high-efficiency laser emission from Nd:YVO4 at the fundamental wavelength of 1342 nm and its 671 nm second harmonic obtained by intra-cavity frequency doubling in an LBO nonlinear crystal are investigated under pumping by diode laser at 880 nm (on the 4F3/2→4I13/2 transition). The end-pumped Nd:YVO4 crystal yielded a continuous-wave output power of 9.6 W at 1342 nm for 18.9 W of absorbed pump power. The slope efficiency measured with respect to the absorbed pump power is 60%. An output of 5.5 W at 671 nm was obtained by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 29%. Comparative results obtained for the pump with a diode laser at 808 nm (on the 4F5/2→4I13/2 transition) are given in order to prove the advantages of the 880 nm wavelength pumping.