Vanadium disulfide for ultrafast photonic application

The investigation of two-dimensional (2D) nonlinear optical materials offers a promising way to construct the high-performance optical devices in fundamental and industrial applications because of their rich distinct optoelectronic properties. Herein, by utilizing the liquid exfoliation method, vanadium disulfide (VS₂) nanosheets are prepared and the thickness is measured to be 3.16 nm. In addition, we have fabricated the VS₂-based optical device and the nonlinear optical property is characterized with modulation depth of 23.97%. By using VS₂ as saturable absorber, a high stable passively mode-locking Er-doped fiber laser is obtained with pulse duration of 169 fs and the largest average output power of 70.5 mW. The slope efficiency is up to 7.9%. In comparison to recent results of mode-locking fiber lasers with 2D materials, the VS₂-based fiber laser demonstrates better performance. To the best of our knowledge, this is the first example of using VS₂ for generating femtosecond mode-locked laser pulse. Our experimental results not only reveal VS₂ ultrafast photonics application, but also advance the high-performance applications for information science and nonlinear optics.