Theoretical and experimental investigations on Nb₂CT_x MXene Q-switched Tm:YAP laser at 2 μm for the nonlinear optical response

In this paper, the Nb₂CT_x MXene nanosheets were fabricated and the corresponding microstructures were investigated. The nonlinear optical response was illustrated by open aperture Z-scan and I-scan methods. The ground and the excited state absorption cross-sections of 2D Nb₂CT_x MXene were also investigated. As the saturable absorber (SA), the Nb₂CT_x MXene was applied in the passively Q-switched Tm:YAP laser. 1.96 μs Q-switched pulses with 3.97 W peak power were achieved at the repetition frequency of 80 kHz. Further theoretical model was built by using the coupled rate equations in simulating the dynamic process of the passively Q-switched Tm:YAP laser. The numerical simulation results are fundamentally in agreement with the experimental results, which proves the Nb₂CT_x MXene can be a good potential nanomaterial for further optoelectronic applications. (paper)