Few-layer bismuthene for 1-μm ultrafast laser applications

Bismuthene, as a new two-dimensional (2D) material made up of diazo metal elements, has drawn massive attention for its unique electronic, mechanical, and quantum properties. However, the nonlinear optical properties of bismuthene in 1-µm region, especially their applications for ultrafast photonics and internal ultrashort pulse dynamics, has seldom been explored yet. In this work, we investigate the few-layer bismuthene characterizations and apply it as a saturable absorber (SA) in a 1-μm ultrafast pulse generation. Thanks to the narrow bandgap of bismuthene and tapered fiber structure, A special noise like pulse has been obtained. The dynamics is also quite different from previous observed pulses, whose intensity ratio of coherent peak and envelope components is of around 5:4 from the autocorrelation trace. It’s demonstrated that the abnormal noise-like pulses contain more uniform-intensity sub pulses. This proposed pulsed fiber laser based on bismuthene SA source is well suitable for some applications such as material processing, optical logics etc.