Enhanced optical nonlinearities in Ti3C2 MXene decorated Fe3O4 nanocomposites for highly stable ultrafast pulse generation

Abstract

In the present work, we proposed a facile strategy to synthesize the Fe3O4/Ti3C2 MXene composite. The morphology and structures of Fe3O4/Ti3C2 MXene were investigated to confirm the interaction. Moreover, the conventional open- and closed-aperture (OA/CA) Z-scan experiments were implemented to work out the nonlinear optical properties at 1 μm. The large effective nonlinear absorption coefficient βeff, nonlinear refractive index n2, third-order susceptibility |χ(3)| were −4.39 cm MW−1, -2.9 × 10−3 cm2 GW−1, 1.5 × 10−10 esu, respectively. In addition, based on the photogenerated carrier separation and transfer model, a set of rate equations was established to interpreter the nonlinear optical dynamics. The recovery lifetimes were estimated in ∼10 ps level, while the carrier separation and transfer times were in sub-ps level. Furthermore, the tapered-microfiber Fe3O4/Ti3C2 MXene composite was employed as the saturable absorber in the Er-doped fiber laser (EDFL) and the Yb-doped fiber laser (YDFL). In the EDFL, a conventional soliton operation was realized at 1555 nm with a minimum pulse duration of 773 fs and a high signal-to-noise ratio (SNR) of 72 dB. While in the YDFL, a dissipative soliton was achieved with a pulse duration of 677 ps and a high SNR of 82 dB. Our work confirmed that Fe3O4/Ti3C2 MXene hybrid possesses excellent nonlinear optical properties and benefits the ultrafast photonics applications.