Passively Q-switched 2.3 μm Tm:YVO₄ laser using a Cr:ZnS saturable absorber

A diode-pumped wavelength switchable passively Q-switched 2.3 μm Tm:YVO₄ laser was demonstrated in this work. A Cr:ZnS saturable absorber was introduced into the cavity for initiating passive Q-switching. With the increase of the absorbed pump power, the passively Q-switched laser could be switched from the single wavelength of 2366 nm to the dual wavelength of 2290 and 2360 nm. The pulse duration and pulse repetition frequency could be tuned in the ranges of 0.745-1.782 μs and 2.9-43.4 kHz, respectively. The pulse energy and peak power were estimated to be 7.5 μJ and 10 W, respectively, at an absorbed pump power of 12 W.