Excellent Q-switching operations modulated by new two-dimensional (2D) saturable absorber (SA) materials with stable performance is a hot topic in all-solid-state pulsed laser research. In this work, the watt-level high-stability passive Q-switching operation in a solid-state Nd:YVO4 laser utilizing the 2D germanene nanosheets as SA was first realized. The nonlinear optical properties of the germanene nanosheets (Ge-Ns) were characterized by experimental means. The stable Q-switched pulse sequence was acquired with a 60.6 ns narrowest pulse width and a 528.6 kHz maximal repetition rate. The average output power of 0.965 W and the corresponding pulse peak power of 30.12 W are obtained under the pump power of 7 W. The findings of the experiments demonstrate that germanene material has remarkable nonlinear optical properties and can be used as an excellent saturable absorber in the field of optical pulse modulation.

In this paper, we report the first Q‐switching operation utilizing black phosphorus (BP)/SnSe2 heterojunction as the saturable absorber (SA) in an Er‐doped fiber laser. The BP/SnSe2 heterojunction was prepared by the liquid phase combination method and its properties were observed. Stable Q‐switching operations were achieved based on the BP/SnSe2 SA. The maximum peak power of 71.27 mW and the minimum pulse width of 910 ns were produced, respectively. This paper demonstrates the pulse modulation characteristics of BP/SnSe2 heterojunction SA in the midinfrared region for the first time, laying an important foundation for the application of heterojunction based on BP and two‐dimensional transition metal dichalcogenides.

In order to investigate the pulse modulation potential of SnSe2 in all-solid-state lasers, an active and passive dual-loss-modulated (APDM) Q-switched and mode-locking (QML) Nd:YVO4 laser was realized by employing an acousto-optic modulator (AOM) and a 5.9 nm thick SnSe2 saturable absorber (SA). The significant pulse compression ability of SnSe2 film was found experimentally, and sub-nanosecond mode-locking pulses with large peak power were obtained. The average output power, pulse energy, and pulse width versus the pump power were measured. With a pump power of 8.5 W, 242 ps mode-locking pulses with a pulse peak power of 231.4 kW were realized successfully. The experimental results also show that the SnSe2-based APDM QML laser has great potential in generating sub-nanosecond pulses with large peak power and high stability.