Passively Q-switched Nd: YVO₄ laser based on Fe₃O₄ nanoparticles saturable absorber

We report on a passively Q-switched Nd:YVO₄ laser at 1064.34 nm by using the ferroferric-oxide (Fe₃O₄) nanoparticles (FONPs) saturable absorber (SA). It is corroborated that the FONPs SA exhibits a large nonlinear saturable absorption property with the modulation depth of 2.49% at the laser wavelength of 1 μm. By inserting the novel SA into a V-type Nd:YVO₄ laser cavity, we obtain the shortest pulse duration of 53 ns with a repetition rate of 576.4 kHz. The corresponding average output power, single pulse energy, and peak power are 104 mW, 0.18 μJ, and 3.53 W, respectively. To the best of our knowledge, it is the first time to experimentally confirm the application of FONPs in a pulsed Nd:YVO₄ solid state laser. The parameters of the pulse width, average output power, and peak power are superior to those in the reported pulsed fiber lasers with FONPs SA so far.