Sensitive saturable absorption response of large-size topological insulator and application in low-threshold solid-state pulsed laser

In this work, the nonlinear saturable absorption of topological insulator Bi₂Te₃ and application in solid-state pulsed laser have been investigated. The highly sensitive saturable absorption of few 2.0 W/cm² and stable Q-switching operation were investigated and achieved in a 1.0 μm Nd:YVO₄ laser as the threshold absorbed pump power was only 31 mW. This is the lowest in passively Q-switched solid-state lasers to the best of our knowledge. The Q-switched pulses as short as 97ns with an average power of 18.6 mW was demonstrated as pumped with 203mW. In addition, mode locking operation was observed. These results prove the potential of the Bi₂Te₃ sheets for efficiently producing high-energy short pulses in miniature and integrated laser system without the need for high excitation intensity.