Atomically transition metal dichalcogenides heterostructures for ultrafast photonics

We report on a type of optical modulator based on MoS₂/graphene/WS₂ Van der Waals heterostructures (VdWHs) acted as excellent saturable absorber (SA) for ultrafast fiber laser systems. After embedding our SA in an Erbium-doped fiber laser with a ring cavity, passive mode-locking operation could be achieved with great laser performances (e.g., ultrafast pulse duration of ~1.96ps, and average output power of 1.02mW). In addition, stacking different 2D materials with various orders, the nonlinear optical properties could also be adjusted to obtain desired SAs. The results indicate that VdWHs offer a great platform to engineer novel ultrafast photonics devices with desired properties.