Ta2C MXene: Nonlinear optical properties and application in femtosecond fiber laser

Broadband optical response and strong optical nonlinearity have enabled MXenes to be applied in numerous ultrafast photonic devices. Here, we explored the nonlinear optical properties of a novel MXene, Ta2C, and demonstrated a femtosecond fiber laser with a Ta2C-based saturable absorber (SA). First-principles calculations were employed to fully reveal the structural and electronic properties of the Ta2C MXene. The third-order nonlinear optical properties of the as-prepared Ta2C nanosheets were measured from the visible to near-infrared regime by the commonly used open-aperture Z-scan technique. Its maximum nonlinear absorption coefficient was fitted to be −0.42 cm/GW, implying its broad application prospects in nonlinear photonic devices. Moreover, Ta2C MXene-coated microfibers as SAs were integrated into erbium-doped fiber laser cavities. Long-term stable mode-locked pulses centered at 1560.1 nm were generated by the constructed laser device. The ultrashort pulse duration of about 774 fs and high signal-to-noise ratio of over 50 dB indicate that Ta2C MXene is a promising material for generating ultrafast pulses.