MXene, as a novel 2D crystal material, possessing tunable bandgap, low optical attenuation and broadband nonlinear optical responses that may promote the fabrications of advanced electro-photonics devices has gathered remarkable attention recently. However, current investigations of 2D crystals for photonics devices suffer from the limitations of reproducibility, scalability, and compatibility. Inkjet printing is one of the powerful additive manufacturers that facilitate well-controlled, low-cost, scalable and small-footprint electro-photonics devices on myriad substrates. Herein, we directly inkjet printed MXene nanosheets in laser resonators with both fiber and free-space geometrics, and achieved extensive spectral band ultrafast laser operations from near- to the mid-infrared regime with pulse duration going to 100 femtoseconds. The demonstrations of versatile inkjet-printed devices based on MXene, while forthputting its distinct electro-optical properties, may allow the realizations of advanced MXene enable photonics devices shortly.

Owing to its thickness-modulated direct energy band gap, relatively strong light–matter interaction, and unique nonlinear optical response at a long wavelength, few-layer black phosphorus, or phosphorene, becomes very attractive in ultrafast photonics applications. Herein, we synthesized a graphene/phosphorene nano-heterojunction using a liquid phase-stripping method. Tiny lattice distortions in graphene and phosphorene suggest the formation of a nano-heterojunction between graphene and phosphorene nanosheets. In addition, we systematically investigate their nonlinear optical responses at different wavelength regimes. Our experiments indicate that the combined advantages of ultrafast relaxation, broadband response in graphene, and the strong light–matter interaction in phosphorene can be combined together by nano-heterojunction. We have further fabricated two-dimensional (2D) nano-heterojunction based optical saturable absorbers and integrated them into an erbium-doped fiber laser to demonstrate the generation of a stable ultrashort pulse down to 148 fs. Our results indicate that a graphene/phosphorene nano-heterojunction can operate as a promising saturable absorber for ultrafast laser systems with ultrahigh pulse energy and ultranarrow pulse duration. We believe this work opens up a new approach to designing 2D heterointerfaces for applications in ultrafast photonics and other research. The fabrication of a 2D nano-heterojunction assembled from stacking different 2D materials, via this facile and scalable growth approach, paves the way for the formation and tuning of new 2D materials with desirable photonic properties and applications.

In recent years, MXene has become a hotspot because of its good conductivity, strong broadband absorption, and tunable band gap. In this contribution, 0D MXene Ti₃C₂T_x quantum dots are synthesized by a liquid exfoliation method and a wideband nonlinear optical response from 800 to 1550 nm is studied, which have a larger nonlinear absorption coefficient β of –(11.24 ± 0.14) × 10^–2 cm GW^–1. The carrier dynamic processes of 0D MXene are explored with ultrahigh time resolution nondegenerate transient absorption (TA) spectroscopy, which indicates that the TA signal reaches its maximum in 1.28 ps. Furthermore, 0D MXene is used to generate ultrashort pulses in erbium or ytterbium‐doped fiber laser cavity. High signal‐to‐noise (72 dB) femtosecond lasers with pulse durations as short as 170 fs with spectrum bandwidth of 14.8 nm are obtained. Finally, an ultranarrow fiber laser based on 0D MXene is also investigated and has a full width at half maximum of only 5 kHz, and the power fluctuation is less than 0.75% of the average power. The experimental works prove that 0D MXene is an excellent SA and has a promising application in ultrafast and ultranarrow photonics.

Low threshold ultrafast fiber lasers in 1.5 based NbSe ₂ quantum dots saturable absorbers have been successfully fabricated and investigated.