Diode-pumped acousto-optical Q-switched 912 nm Nd:GdVO₄ laser and extra-cavity frequency-doubling of 456 nm deep-blue light emission

In this paper, a diode-pumped acousto-optical (A-O) Q-switched 912 nm Nd:GdVO₄ laser and pulsed 456 nm deep-blue light emission by extra-cavity frequency-doubling are demonstrated. To compensate the serious thermal-lensing effect in laser crystal, a compact unstable resonator is used. At an incident pump power of 49.5 W, a maximum average output power of 2.3 W 912 nm laser is obtained at 10 kHz, corresponding to an optical conversion efficiency of 4.6% and a slope efficiency of 9.2%. Minimum pulse width of 20 ns and maximum peak power of 10.5 kW 912 nm laser are achieved at a pump power of 45.3 W. Using a BiBO crystal as the frequency-doubler, maximum average output power of 623 mW 456 nm deep-blue light is obtained at 10 kHz, with a pulse width of 21.3 ns and a peak power of 2.3 kW. Moreover, stable operating repetition rate of 912 nm laser and 456 nm deep-blue light is up to 100 kHz.