High-repetition-rate Q-switched fiber laser with high quality topological insulator Bi_2Se_3 film

Abstract

We demonstrated a high-repetition-rate Q-switched fiber laser with topological insulator Bi₂Se₃ absorber. The absorber was made into a film structure by spin-coating method using few-layer Bi₂Se₃ nano-platelets which had regular shape. The uniform film had a low saturable optical intensity of 11 MW/cm(2), which is the lowest saturable optical intensity in the saturable absorbers made by topological insulator till now. By inserting the absorber film into an Erbium-doped fiber laser, a high-repetition Q-switched laser with the repetition rates from 459 kHz to 940 kHz was achieved. The maximum output power was 22.35 mW with the shortest pulse duration of 1.9 μs. To the best of our knowledge, both of the repetition rate and the output power were the highest values among the Q-switched fiber lasers with topological insulator absorber.