Compact and efficient passively Q-switched laser at 473 nm with an Nd:YAG/YAG/Cr:YAG/YAG multifunctional composite crystal.

An Nd:YAG/YAG/Cr:YAG/YAG composite crystal and an LBO crystal were used to generate a passively Q-switched frequency-doubling 473 nm blue laser for the first time, to the best of our knowledge. The result demonstrated that the slope efficiency of this system reaches 18%, which is the highest in all the passively Q-switched 473 nm laser systems reported, to the best of our knowledge. Under the pumped power of 8.64 W, the maximum average output power of 0.93 W was obtained with a pulsewidth of 78 ns, and the repetition rate of 18.5 kHz.