56-ps passively Q-switched diode-pumped microchip laser

Abstract
We passively Q switched a diode-pumped Nd:YVO4 microchip crystal with an antiresonant Fabry–Perot saturable absorber and achieved single-frequency pulses as short as 56 ps. We can vary the pulse width from 56 ps to 30 ns and the repetition rate from 27 kHz up to 7 MHz by changing the design parameters of the saturable absorber and the pump power.