Efficient passively Q-switched laser operation of Yb in the disordered NaGd(WO4)2 crystal host

Efficient passively Q-switched laser operation of the disordered Yb: NaGd(WO4)(2) crystal is demonstrated for the first time to our knowledge with a Cr4+:YAG saturable absorber by diode end pumping. 2.05 W of average output power at a pulse repetition frequency of 13.3 kHz was obtained at an absorbed pump power of 7.7 W, with a slope efficiency of 40%. The energy and duration of the generated laser pulse were 154 mu J and 33 ns, respectively, corresponding to a peak power of 4.67 kW. In continuous-wave operation, the Yb: NaGd(WO4)(2) laser yielded an output power of 5.5 W with an optical-optical efficiency of 51%. (C) 2007 Optical Society of America