Generation of Q-switched pulse by Bi₂Se₃ topological insulator in Yb:KGW laser

A Q-switched Yb:KGW solid-state laser using topological insulator Bi₂Se₃ as a saturable absorber was demonstrated experimentally for the first time. The Bi₂Se₃ saturable absorber was fabricated in a film on a highly reflective mirror. By inserting this into a Yb:KGW laser, the Q-switched operation was obtained. The highest average output power was 439.4 mW and the corresponding repetition rate, pulse width and pulse energy were 166.7 kHz, 1.6 μs and 2.64 μJ, respectively. To our knowledge, this is the highest output power among topological insulator-modulated lasers with topological insulator absorbers. (letter)