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

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 mu m. The large effective nonlinear absorption coefficient beta(eff), nonlinear refractive index n(2), third-order susceptibility vertical bar chi(3)vertical bar were -4.39 cm MW-1, -2.9 x 10(-3) cm(2) GW(-1), 1.5 x 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 similar to 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. (C) 2021 Elsevier Ltd. All rights reserved.