Monoclinic bismuth vanadate nanoparticles as saturable absorber for Q-switching operations at 1.3 and 2 mu m

We synthesized monoclinic bismuth vanadate (m-BiVO4) nanoparticles via the sol-gel method. The modulation depths were 20.1% and 8.8% at 1.34 and 2 mu m, respectively. Passively Q-switched bulk lasers with m-BiVO4 saturable absorber were demonstrated operating at 1.34 and 2 mu m. At 1.34 mu m, the shortest pulse duration was 355 ns with a pulse repetition frequency of 242.6 kHz, while in a Tm-doped bulk laser at similar to 2 mu m, the minimum pulse width was 540 ns with a pulse repetition rate of 53.7 kHz. Results showed that m-BiVO4 possessed good broadband optical nonlinearities and can be applied for the optical pulse generation.