The novel two-dimensional MXenes have been investigated in the photonics field in areas such as broadband nonlinearity, pulse laser generation and passive photonic diode, and so on. In this contribution, the nonlinear optical response at the visible band and the demand pulse laser generation based on MXenes was initially realized. The few-layer MXene Ti₃C₂T_x was fabricated and utilized as a saturable absorber (SA) to realize passive Q-switched visible bulk laser covering the spectral range of orange (607 nm), red (639 nm), and deep red (721 nm). At the three wavelength, the maximum average output powers and the shortest pulse widths were (111 mW, 426 ns) for 607 nm, (150 mW, 264 ns) for 639 nm, (115 mW, 328 ns) for 721 nm, respectively. Our experimental results indicate the MXene Ti₃C₂T_x SA could be an efficient and promising optical modulator in the visible domain.

γ-graphyne, as a member of two-dimensional carbon materials, has attracted much attentions benefitting from its unique characteristics, such as high carriers mobility, high stability, etc. In the present study, a γ-graphyne saturable absorber (SA) was fabricated and characterized. The linear optical absorption in the spectral range from the visible to mid-infrared as well as the nonlinear optical character of the SA were investigated. The passively Q-switched solid-state lasers emitting at 639 nm, 1342 nm, 1932 nm were realized by using the γ-graphyne SA. The results indicate that the γ-graphyne could be a promising alternative for rare broadband optical modulator.

We demonstrated a passively $Q$-switched visible Pr:YLF laser using the gold nanostars (GNSs) as the saturable absorber (SA). The nonlinear saturable absorption properties at 639 nm were measured, and the modulation and saturable fluence were calculated to be 3% and $0.3\mathrm{GW}/{\mathrm{cm}}^2$, respectively. With the GNSs SA, the efficient passively $Q$-switched lasers were obtained at 639 nm and 721 nm, respectively. The maximum output powers and shortest pulse widths were (256 mW, 168 ns) at 639 nm and (238 mW, 198 ns) for 721 nm. To the best of our knowledge, this is the first time there has been a visible bulk pulse laser using the GNSs as the SA. Our work indicates the GNSs could be excellent and promising optoelectronic devices in the visible domain.

Two-dimensional (2D) Te nanosheets were successfully fabricated through the liquid-phase exfoliation (LPE) method. The nonlinear optical properties of 2D Te nanosheets were studied by the open-aperture Z-scan technique. Furthermore, the continuous wave mode-locked Nd:YVO₄ laser was successfully realized by using 2D Te as a saturable absorber (SA) for the first time, to the best of our knowledge. Ultrashort pulses as short as 5.8 ps were obtained at 1064.3 nm with an output power of 851 mW. This primary investigation indicates that the 2D Te SA is a promising photonic device in the fields of ultrafast solid-state lasers.

Rhenium disulfide (ReS ₂ ), one of the typical representatives of 2D layered transition metals dichalcogenide materials, has attracted widespread attention for its optical modulation properties in lasers. In this letter, a high-quality ReS ₂ nanosheet film-based saturable absorber (SA) was successfully prepared by a liquid phase exfoliation method and employed into a passively Q -switched Ho,Pr:LiLuF ₄ bulk laser operating at 2.95 μm. The maximum output power of 103 mW was obtained with the shortest pulse duration of 676 ns and a repetition rate of 91.5 kHz, corresponding to the single pulse energy of 1.13 μJ and a pulse peak power of 1.67 W, respectively. The results indicate that ReS ₂ is a promising SA for mid-infrared pulse generation.

Two-dimensional (2D) materials own unique band structures and excellent optoelectronic properties and have attracted wide attention in photonics. Tin disulfide (SnS₂), a member of group IV-VI transition metal dichalcogenides (TMDs), possesses good environmental optimization, oxidation resistance, and thermal stability, making it more competitive in application. By using the intensity-dependent transmission experiment, the saturable absorption properties of the SnS₂ nanosheet nearly at 3 μm waveband were characterized by a high modulation depth of 32.26%. Therefore, a few-layer SnS₂ was used as a saturable absorber (SA) for a bulk Er:SrF₂ laser to research its optical properties. When the average output power was 140 mW, the passively Q-switched laser achieved the shortest pulse width at 480 ns, the optimal single pulse energy at 3.78 µJ, and the highest peak power at 7.88 W. The results of the passively Q-switched laser revealed that few-layer SnS₂ had an admirable non-linear optical response at near 3 μm mid-infrared solid-state laser.