Ag/MXene Composite as a Broadband Nonlinear Modulator for Ultrafast Photonics

Nanomaterials with broadband nonlinear responses have attracted wide attention in ultrafast photonics, which have proven to be reliable saturable absorbers to generate broadband pulses. In recent years, combining materials with different characteristics has also become a new research hotspot. Herein, two-dimensional MXene (Ti₃C₂T_x) and metal silver (Ag) nanoparticles were combined to form the Ag/MXene composite by the technique of layer-by-layer spraying with the hot-pressing method, enhancing the nonlinear absorption property of the composite. In addition, the Ag/MXene also exhibited broadband saturable absorption abilities in the measurement of the nonlinear transmittance from 1 to 2 μm. Therefore, the Ag/MXene composite was used as a saturable absorber to modulate pulses in lasers, where the Q-switched pulses based on Ag/MXene were realized in ytterbium-, erbium-, and thulium:holmium-doped fiber lasers for the first time, to the best of our knowledge. The performance of the output pulses including wavelength, power, and stability were also discussed in detail. This work provides more possibilities for the combination of different materials, which promotes the development of broadband lasers based on nanomaterials in the farther mid-infrared band.