Quasi-three-level Nd:GdVO4 laser under diode pumping directly into the emitting level

We present experimental investigation on quasi-three-level operation of Nd:GdVO4 laser under 879 nm laser diode pumping into the emitting level. By using a 5-mm-long, 0.2-at.% bulk crystal, the maximal 3.65 W continuous wave 912 nm laser is obtained under 16.5 W pump power. The slope efficiency is 35.9% and the optical conversion efficiency is 22.1% with respect to the absorbed pump power. The beam quality factor is about 1.83 for 3.0 W output power at 912 nm. The good results demonstrate that the 879 nm direct pumping can also be used in the quasi-three-level systems