MXene Nb2C/MoS2 heterostructure: Nonlinear optical properties and a new broadband saturable absorber for ultrafast photonics

We for the first time demonstrate an all-fiber, ytterbium/erbium/thulium-doped, mode-locked laser system using a MXene/transition metal dichalcogenides (TMDs)-based heterostructure (Nb₂C/MoS₂) as a broadband saturable absorber (SA) to the best of our knowledge. The broadband saturable absorber, fabricated by optical deposited method, integrated MXene Nb₂C/MoS₂ and tapered fiber, exhibits strong nonlinear optical response at wavelengths of 1.0 μm, 1.5 μm and 2 μm. 12.4 ps/96.5 fs/551 fs stable pulses at 1050.00 nm/1597.50 nm/1901.97 nm are achieved, as the shortest pulse durations, respectively, based on the Nb₂C/MoS₂ in ytterbium/erbium/thulium-doped fiber laser to date. Through intracavity dispersion management, the MXene Nb₂C/MoS₂ based erbium-doped cavity can generate a 96.5 fs pulse with a spectral width of 43.36 nm, and both of pulse time and spectral width are the shortest and widest values in an all-fiber laser to date, respectively. Our results validate the broadband operating characteristics of MXene Nb₂C/MoS₂ devices in all-fiber lasers from 1 to 2 μm. The outstanding nonlinear optical properties of MXene Nb₂C/MoS₂ provide extensive prospects for its application in fields such as electronic devices and optoelectronic devices.