Soliton fiber laser mode locked with two types of film-based Bi₂Te₃ saturable absorbers

We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi₂Te₃ with de-ionized water, as well as polyvinyl alcohol (PVA), and then evaporating them in a Petri dish, and the other of which is prepared by directly dropping Bi₂Te₃ solution on the PVA film. Both Bi₂Te₃–PVA films exhibit outstanding features of low loss, high flexibility, and easy synthesis. By incorporating Bi₂Te₃–PVA films into fiber lasers, stable single-soliton emissions are obtained at a low pump power of 13 mW. Our results suggest that the Bi₂Te₃ can work as a promising mode locker for ultrafast lasers, while PVA is an excellent host for fabricating high-performance film-based saturable absorbers.