Nanosecond passively Q-switched Nd: YVO4 laser based on BP/InSe saturable absorber

We report on a compact 808 nm diode-pumped passively Q-switched (PQS) Nd:YVO4 laser at 1064 nm with black phosphorus (BP)/ indium selenide (InSe) heterostructure as a saturable absorber (SA). When the transmission of the output coupler (OC) was 30%, the maximum continuous-wave (CW) output power of 10.3 W was obtained with a slope efficiency of 52.4% under the incident pump power of 22 W. The maximum average output power of 3.1 W was obtained at 9.29 W pump power, corresponding to the repetition rate of 598 kHz and the pulse width of 455 ns during pulse operation, further power scaling was limited by the damage threshold of the saturable absorber mirror (SAM). The results sufficiently validated that two-dimensional (2D) BP/InSe heterostructure could be used as an optical modulator for near-IR pulsed laser sources.