We report the surface morphology and the nonlinear absorption characteristics of MXene VCrC nanosheets prepared by the liquid-phase exfoliation method. The self-made MXene VCrC was applied as a saturable absorber in the Tm:YAP laser experiments, performing excellent Q-switching optical modulation characteristics in infrared range. With this absorber, a stable passively Q-switched 2 μm laser was achieved. Under an incident pump power of 3.52 W, a maximum output power of 280 mW was obtained with a T = 3% output coupler at a repetition frequency of 49 kHz. The corresponding pulse energy and peak power were 5.7 μJ and 6.6 W, respectively. The shortest pulse duration was 658 ns at the repetition rate of 63 kHz with a T = 1% output coupler.

MXene materials have shown numerous useful mechanical and electronic properties, and have been found to possess nice potential in the field of optical modulation. Here, we fabricated a MXene Cr₂C saturable absorber by the liquid-phase exfoliation method, and systemically analyzed the surface morphology and nonlinear properties of the Cr₂C sample. Applying the Cr₂C saturable absorber as a Q-switch in a thulium-doped yttrium aluminum perovskite (Tm: YAP) laser, the shortest single pulse was obtained with a width of 602 ns under an absorbed pump power of 3.3 W at a repetition rate of 55 kHz with a T = 1% output coupler. The maximum output power was obtained with a T = 5% output coupler at a repetition rate of 58 kHz. The obtained maximum pulse energy and peak power were 3.96 μJ and 4.36 W, separately, which reveal that the MXene Cr₂C can be applied as a promising modulation material in the near-infrared pulsed lasers.

Magnesium 2,5-dihydroxyterephthalate (Mg-MOF-74) nanosheets were prepared by liquid-phase exfoliation method. The surface morphology and nonlinear absorption properties of the nanosheets were investigated. Employing the Mg-MOF-74 nanosheets as a saturable absorber, a stable passively Q-switched Tm:YAP laser was successfully realized. Under an incident pump power of 7 W, the average output power of the Q-switched pulses was 1150 mW with a T = 5% output coupler, corresponding to a single-pulse energy of 11.3 μJ and peak power of 25.6 W. Meanwhile, the obtained minimum pulse duration was 313 ns at a repetition rate of 117 kHz with a T = 1% output coupler.