Ultrafast Photonics Applications Based On Evanescent Field Interactions With 2d Molybdenum Carbide (Mo2c)

MXenes have attracted considerable attention for the generation of ultrafast pulsed lasers because of light-matter interactions and excellent saturable absorption characteristics. As a recently developed new member of the MXene family, two-dimensional (2D) molybdenum carbide (Mo2C) exhibits outstanding optical properties. In this study, we synthesized Mo2C nanosheets by using a liquid-phase exfoliation method and studied the nonlinear optical properties of Mo2C nanosheets. The saturation intensity and the modulation depth were measured to be 200 MW cm(-2) and 5.1%, respectively. Moreover, we prepared a mode-locker based on a D-shaped fibre Mo2C saturable absorber (SA) by employing evanescent field interactions. By implementing a D-shaped Mo2C SA into ytterbium-doped and erbium-doped fibre lasers, highly stable mode-locked fibre lasers were demonstrated at the 1 micron and 1.5 micron scales, respectively. A pulse duration as short as 290 fs was obtained in the telecommunication window. The corresponding pulse energy and peak power were 0.86 nJ and 2982 W, respectively. Furthermore, a highly stable picosecond-pulse ytterbium-doped fiber laser with a maximum pulse energy of 0.38 nJ was achieved. Compared to recently reported studies based on Mo2C, our experimental results are more advantageous. Our work indicates that a D-shaped Mo2C SA can be used as a broadband mode-locker for potential applications in ultrafast photonics.