Passively mode-locked Yb:KLu(WO4)2 oscillators

We demonstrate passive mode locking based on the novel monoclinic double tungstate crystal Yb: KLu(WO4)(2). We report the shortest pulses ever produced with an Yb-doped tungstate laser using a semiconductor saturable absorber. A pulse duration of 81 fs has been achieved for an average power of 70 mW at 1046 nm. We compare the performance of the polarization oriented parallel to the N-m- and N-p-crystallooptic axes. Results in the femtosecond and picosecond regime are presented applying either Ti: sapphire or diode laser pumping. The great potential of Yb: KLu(WO4)(2) as an active medium for ultrashort pulses is demonstrated for the first time, to our knowledge. (C) 2005 Optical Society of America.