MXene Core-Shell Nanosheets: Facile Synthesis, Optical Properties, and Versatile Photonics Applications.

In recent years, the transition metal carbonitrides(MXenes) have been widely applied to photoelectric field, and better performance of these applications was achieved via MXene complex structures. In our work, we proposed a MXene core-shell nanosheet composed of a Ti2C (MXene) phase and gold nanoparticles, and applied it to mode-locked and single-frequency fiber laser applications. The optoelectronic results suggested that the performances of these two applications were both improved when MXene core-shell nanosheets were applied. As a result, we obtained a mode-locking operation with 670 fs pulses, and the threshold pump power reached to as low as 20 mW. Besides, a single-frequency laser with the narrowest linewidth of ~1 kHz is also demonstrated experimentally. Our research work proved that MXene core-shell nanosheets could be used as saturable absorbers (SAs) to promote versatile photonic applications.