457 nm blue laser generation by intracavity frequency doubling of acousto-optically Q-switched Nd:YVO₄ laser

Pulsed blue laser has important applications in underwater detection, underwater communication and remote sensing. According to the ABCD matrix of Gaussian beam's propagation, a Z-type cavity insensitive to thermal lens effect is designed. By use of 808 nm laser diode (LD). the ⁴F_3/2 → ⁴I_9/2 quasi-three-level transition in Nd:YVO₄ crystal is realized at room temperature. Stable pulsed 457 nm blue laser with high repetition rate and high peak power is demonstrated by acousto-optically Q-switching and intracavity frequency doubling. When the incident pump power is 30 W, the maximum single pulse energy of 56 μJ, pulse duration of 217 ns and peak power of 258 W are achieved at 10 kHz; the maximum average power of 760 mW, pulse duration of 261 ns and peak power of 146 W are obtained at 20 kHz. The fluctuation of the blue laser power is less than 2.0% within the given 20 min at the maximum output power.