Self-Q-switchedandwavelength-tunabletungstendisulfide-basedpassivelyQ-switchedEr:Y2O3ceramiclasers

We report on diode-pumped Er:Y2O3 ceramic lasers at about 2.7 μm in the tunable continuous-wave, selfQ-switching and tungsten disulfide（WS2）-based passively Q-switching regimes. For stable self-Q-switched operation, the maximum output power reaches 106.6 m W under an absorbed power of 2.71 W. The shortest pulse width is measured to be about 1.39 μs at a repetition rate of 26.7 kHz at maximum output. Using a spin-coated WS2 as a saturable absorber, a passively Q-switched Er:Y2O3 ceramic laser is also realized with a maximum average output power of 233.5 m W（for the first time, to the best of our knowledge）. The shortest pulse width decreases to 0.72 μs at a corresponding repetition rate of 29.4 kHz, which leads to a pulse energy of 7.92 μJ and a peak power of 11.0 W. By inserting an undoped YAG thin plate as a Fabry–Perot etalon, for the passive Q switching, wavelength tunings are also demonstrated at around 2710, 2717, 2727, and 2740 nm.