Near-infrared all-fiber mode-locked laser based on vanadium carbide nanosheets

Vanadium carbide (V 2 C), a newly developed MXene, has been theoretically predicted to be an excellent nonlinear optical materials. Here, few-layer V 2 CT x nanosheets were synthesized by liquid phase exfoliation (LPE) method. Z-scan measurement was performed to explore their third-order nonlinear optical properties, highlighting the strong nonlinearities of few-layer V 2 CT x nanosheets. And the effective nonlinear absorption coefficient was determined to be − 98.3 cm/MW, corresponding to the imaginary part of the third-order nonlinear effects was obtained to be − 1.106 × 10 −8 esu. In addition, microfiber-based few-layer V 2 CT x saturable absorber (SA) was fabricated by optical deposition method and the saturable absorption characteristic was measured by I-scan technique. The Yb-doped and Er-doped fiber lasers (YDFLs and EDFLs) were performed by inserting microfiber-based few-layer V 2 CT x SA into the ring cavity. And the stable mode-locked operation was realized with super high signal- noise ratio (SNR). Our work systematically reveals that few-layer V 2 CT x nanosheets should be an excellent SA for ultrafast photonics in the near-infrared band.