Passively Q-switched 2 μm laser based on graphene/BN heterostructure as saturable absorber

We have achieved a nanosecond solid-state Q-switched Tm:YAP laser based on a graphene/BN heterojunction saturable absorber at 1.9 & mu;m for the first time. When the pump power is 28.9 W, the Tm:YAP laser generated stable laser pulses with a repetition rate of 188.43 kHz, a minimum pulse duration of 607 ns, a maximum single pulse energy of 19.43 & mu;J and a peak power close to 32 W, which showed enhanced saturable absorption prop-erties than monolayer graphene (738 ns, 176.51 kHz).The experimental results substantiated that graphene/BN heterojunction is a promising saturable absorption material for the preparation of high-performance mid-infrared pulsed lasers. The resulting nanosecond 2 & mu;m Q-switched pulsed lasers provide a momentous impetus for advancing the fields of laser radar, laser surgery and other fields.