NbSe₂/PtTe₂ heterostructures as saturable absorbers for mid-infrared pulsed solid-state lasers

We have realized for the first time, to the best of our knowledge, a 2 µm nanosecond solid-state passive Q-switched Tm:YAP laser based on a <i>N</i> <i>b</i> <i>S</i> <i>e</i> ₂/<i>P</i> <i>t</i> <i>T</i> <i>e</i> ₂ heterojunction saturable absorber. At an incident pump power of 12.69 W, the Tm:YAP laser produces stable laser pulses with a minimum pulse width of 818 ns, a maximum single-pulse energy of 15.48 µJ, and a peak power of 18.93 W at a repetition rate of 79.44 kHz. The comparison results show enhanced saturable absorption performance compared to single <i>N</i> <i>b</i> <i>S</i> <i>e</i> ₂ (1 µs, 70.32 kHz) and single <i>P</i> <i>t</i> <i>T</i> <i>e</i> ₂ (1.31 µs, 71.97 kHz). The experimental results confirm that the <i>N</i> <i>b</i> <i>S</i> <i>e</i> ₂/<i>P</i> <i>t</i> <i>T</i> <i>e</i> ₂ heterojunction is a promising saturable absorption material that can be used to realize high-performance mid-infrared pulsed lasers. The resulting nanosecond 2 µm Q-switched pulsed laser will play an important role in atmospheric monitoring, lidar, and other fields, and can provide a strong driving force.