In this paper, a novel 2D ternary chalcogenide Ta2NiSe5 is fabricated into a saturable absorber by using the liquid phase exfoliation (LPE) method and successfully applied to the passive Q-switching experiment of Tm:YAP all-solid-state laser at 2 µm. The nonlinear optical absorption (NOA) properties of Ta2NiSe5 at 2 µm was measured by using an open-aperture Z-scan method, showing saturation fluence and modulation depth of 400 µJ/cm2 and 24%, respectively. By using Ta2NiSe5 as saturable absorber, the shortest pulse width of 740 ns and maximum repetition frequency of 71 kHz are obtained, respectively. This results prove that the Ta2NiSe5 is an excellent saturable absorber to achieve passively Q-switched laser at 2 µm, for the first time to the best of our knowledge.

In this study, a novel ternary alloy using Mo 0.5 Re 0.5 S 2 as a saturable absorber (SA) is prepared by liquid phase exfoliation method and successfully applied to a passively Q-switched Tm:YAlO 3 (Tm:YAP) bulk laser for the first time. The nonlinear SA effect of the prepared Mo 0.5 Re 0.5 S 2 SA at 2 μm is characterized using the open-aperture Z-scan technique and results in a saturable intensity of 5.62 μJ cm −2 and modulation depth of 7.92%. Using Mo 0.5 Re 0.5 S 2 as an SA, a 2 μm Q-switched Tm:YAP laser is realized, generating a maximum output power of 0.957 W with a shortest pulse width of 857.5 ns and a maximum repetition rate of 95 kHz. The corresponding single pulse energy and peak power are 10.1 μJ and 11.5 W, respectively. These achievements indicate that Mo 0.5 Re 0.5 S 2 could be an excellent and reliable SA for mid-infrared laser applications, and ternary transition metal disulfide alloys will bring new application opportunities to optoelectronic devices in the future.