A Novel 1,066 nm Nd:Gd 0 . 69 Y 0 . 3 NbO 4 Passively Q -Switched Pulse-Burst Laser

We demonstrate for the first time a Cr 4+ :YAG passively Q -switched 1066 nm pulse-burst laser under 879 nm direct pump with a novel Nd:Gd 0 . 69 Y 0 . 3 NbO 4 crystal. The output laser characteristics with different pump repetition rates and different Cr 4+ :YAG initial transmission are studied. Without the Cr 4+ :YAG, we obtain a maximum output energy of 2.55 mJ at an absorbed pump energy of 5.79 mJ with the highest 48% slope efficiency. The pulse-burst laser contains a maximum of 7 pulses for a Cr 4+ :YAG initial transmission of 55% and a pump repetition rate of 1 kHz. The single-pulse energy and narrowest pulse width reach 160 μ J and 5.5 ns at 38.2 kHz, with a peak power of 32 kW.