Reserch on picosecond passively Q-switched microchip laser

Compact and simple pico second lasers are required in many applications like fine material processing. we have been developing a pulsed fiber laser which consist of a fiber amplifier system and a passively Q-switched microchip laser as a seed source. In this presentation, we report the test results of the passively Q-switched microchip laser. The pump source is a diode laser coupled to single mode fiber with the wavelength of 808 nm and the maximum power of 214 mW. The microchip is composed of a combination of gain medium and a saturable absorber, and we used two types of microchip. There are differences in the thickness of the gain medium and dopant ratio of neodymium. The gain medium is Nd:YVO₄. The thickness are 100 μm with 3% neodymium doping and 300 μm with 2% neodymium doping. As a result, We obtained 6.1 mW laser output with 90 ps pulse width, 1.3 MHz repetition frequency at short gain medium. And the other one got 14 mW laser output power with 161ps pulse width, 1.4 MHz repetition frequency. The single longitudinal operation was achieved for both of them.