Femtosecond ultrafast pulse generation with high-quality 2H-TaS2 nanosheets via top-down empirical approach.

Tantalum disulfide (TaS2), an emerging group VB transition metal dichalcogenide, with unique layered structure, rich phase diagrams, metallic behavior, higher carrier concentration and mobility is emerging as a prototype for revealing basic physical phenomena and developing practical applications. However, its photonics properties and even engineering-related processes are still rare. Here, the top-down experiment demonstration, including synthesis, thickness optimization and nonlinear optical application, has been reported. In addition, the ultrafast (∼373 fs) erbium-doped fiber pulse with a small time-bandwidth product (∼0.34) and long-term stability (∼25 days) was realized using the nonlinear absorption properties of the high-quality 2H-TaS2 nanosheet. These results suggest an experimental route for further ultrafast photonics exploration based on metallic transition metal dichalcogenides.