Are graphene-BiTe van der Waals heterostructure-based saturable absorbers promising for solid-state Q-switched lasers?

This Letter compared the absorption characteristics of a homemade graphene-BiTe (G-B) van der Waals heterostructure to a BiTe topological insulator (TI) with a similar preparation method and number of layers. The results indicate that the G-B heterostructure can tremendously enhance the modulation depth and saturable intensity. In addition, a passively Q-switched laser at 1.06 μm with a G-B heterostructure as a saturable absorber (SA) was demonstrated for the first time, to the best of our knowledge. Compared to BiTe TI, the G-B heterostructure Q-switched laser had better laser performance, indicating that a G-B heterostructure is a promising SA candidate for a 1 μm laser.