Actively Q-switched intracavity Nd:YVO4/GdVO4 Raman laser operating with multiple Raman shifts of 259, 882 and 890 cm-1

A diode-pumped acousto-optic Q-switched crystal Raman laser operating at multi-wavelength is reported, in which a c-cut Nd:YVO4 crystal was used as the self-Raman medium and a c-cut GdVO4 crystal was used as the other Raman medium. Benefited from the overlapping gain at the Raman shift of 259 cm(-1) in the two crystals, the corresponding cascade Stokes light efficiently oscillated, and the 1177, 1178 nm lights corresponding to the primary Raman-shifts of the two crystals oscillated with the 1097 nm laser. The laser configuration was investigated at pulse repetition frequencies (PRFs) of 10, 20, and 30 kHz. With an incident pump power of 8.62 W, the highest average Raman laser output of 1.31 W composed of 1097, 1129, 1177 and 1178 nm lights was obtained at the PRF of 20 kHz. The 1163 nm light corresponding to the third-Stokes light of the Raman shift of 259 cm(-1) only arose at the PRF of 10 kHz when the incident pump power exceeded 6.37 W.