Graphene and the following derivative 2D materials have been demonstrated to exhibit rich distinct optoelectronic properties, such as broadband optical response, strong and tunable light–mater interactions, and fast relaxations in the flexible nanoscale. Combining with optical platforms like fibers, waveguides, grating, and resonators, these materials has spurred a variety of active and passive applications recently. Herein, the optical and electrical properties of graphene, transition metal dichalcogenides, black phosphorus, MXene, and their derivative van der Waals heterostructures are comprehensively reviewed, followed by the design and fabrication of these 2D material‐based optical structures in implementation. Next, distinct devices, ranging from lasers to light emitters, frequency convertors, modulators, detectors, plasmonic generators, and sensors, are introduced. Finally, the state‐of‐art investigation progress of 2D material‐based optoelectronics offers a promising way to realize new conceptual and high‐performance applications for information science and nanotechnology. The outlook on the development trends and important research directions are also put forward.

The year 2019 marks the 10th anniversary of the first report of ultrafast fiber laser mode-locked by graphene. This result has had an important impact on ultrafast laser optics and continues to offer new horizons. Herein, we mainly review the linear and nonlinear photonic properties of two-dimensional (2D) materials, as well as their nonlinear applications in efficient passive mode-locking devices and ultrafast fiber lasers. Initial works and significant progress in this field, as well as new insights and challenges of 2D materials for ultrafast fiber lasers, are reviewed and analyzed.

Recently, 2D materials are in great demand for various applications such as optical devices, supercapacitors, sensors, and biomedicine. MXenes as a kind of novel 2D material have attracted considerable research interest due to their outstanding mechanical, thermal, electrical, and optical properties. Especially, the excellent nonlinear optical response enables them to be potential candidates for the applications in ultrafast photonics. Here, a review of MXenes synthesis, optical properties, and applications in ultrafast lasers is presented. First, aqueous acid etching and chemical vapor deposition methods for preparing MXenes are introduced, in which the storage stability and challenges of the existing synthesis techniques are also discussed. Then, the optical properties of MXenes are discussed specifically, including plasmonic properties, optical detection, photothermal effects, and ultrafast dynamics. Furthermore, the typical ultrafast pulsed lasers enabled by MXene-based saturable absorbers operated at different wavelength regions are summarized. Finally, a summary and outlook on the development of MXenes is presented in the perspectives section.

In recent years, a variety of 2‐dimensional (2D) materials including graphene, topological insulators, transition metal dichalcogenides, and black phosphorus have been utilized in photonics and optoelectronics applications. Since the mid‐infrared (MIR) region has a significant role in various fields, rapid progress has been made on photonics and optoelectronics applications using 2D materials. Herein, the progress in the photonics devices that exploit the unique properties of 2D materials for a range of MIR applications is summarized, focusing on ultrafast light generation, MIR light modulation, and photodetection. By taking advantage of ultrafast light response, broadband absorption, and high carrier mobility of 2D materials, femtosecond lasers, broadband optical modulators, and high‐responsivity photodetectors are achieved. Some perspectives on 2D material‐based MIR photonics are highlighted. Due to their MIR bandgaps, small size, high carrier mobility, and easy integration, 2D materials are appealing for MIR photonics applications. Moreover, the availability of an increasingly broad library of 2D materials with variable electronic and optical properties, and the ability to be thinned and restacked into functional and complex assembled structures, enable the development of a highly integrated MIR photonic chip, which will make information technology greener, faster, and lower in energy consumption.

Microresonator based Kerr frequency comb generation has many attractive features, including ultrabroad spectra, chip-level integration, and low power consumption. Achieving precise tuning control over the comb frequencies will be important for a number of practical applications, but has been little explored for microresonator combs. In this paper, we characterize the thermal tuning of a coherent Kerr frequency comb generated from an on-chip silicon nitride microring. When the microring temperature is changed by ~70 °C with an integrated microheater, the line spacing and center frequency of the comb are tuned respectively by -253 MHz (-3.57 MHz/°C) and by -175 GHz (-2.63 GHz/°C); the latter constitutes 75% of the comb line spacing. From these results we obtain a shift of 25 GHz (362.07 MHz/°C) in the comb carrier-envelope offset frequency. Numerical simulations are performed by taking into account the thermo-optic effects in the waveguide core and cladding. The temperature variation of the comb line spacing predicted from simulations is close to that observed in experiments. The time-dependent thermal response of the microheater based tuning scheme is characterized; time constants of 30.9 μs and 0.71 ms are observed.

Q‐switched fiber lasers are of great interest in industrial material processing, nonlinear frequency conversion, spectroscopy etc. However, passive Q‐switching possesses drawbacks of degradation and failure of the saturable absorber and the difficulty in accurate modification of the repetition rate. To overcome these issues, active Q‐switching that can normally modulate the cavity quality‐factor by an externally‐driven Q‐switcher is in high demand. Herein, an actively Q‐switched laser with antimonene‐based all‐optical modulator is devised based on the high photo‐thermal efficiency (48%) and broadband response in antimonene. It is demonstrated that this actively modulated laser represents all‐optically tunable output parameters (e.g., output repetition rate), environmental stability, and easy synchronization. It is anticipated that this actively antimonene‐based all‐optical modulator with advantages of large modulation depth, low energy consumption, and high conversion efficiency has great potential in all‐optical information processing and pulsed laser engineering.

Investigations into semiconductor nanomaterials from both an academic and industrial point of view are of great significance. Selenium (Se) nanostructures, as narrow bandgap semiconductors, have a variety of potential applications in the fabrication of many high-performance devices. The past decades have witnessed rapid development in new strategies for synthesizing Se nanostructures with controlled sizes, shapes, and structures, whose diverse structure-dependent nature enables functional Se nanomaterials to have great potentials for modern applications. This review focuses on the synthesis and morphology control of intriguing Se nanostructures, the latest progress in understanding the fundamental properties of Se nanostructures, and the recent advances in high-performance Se nanomaterial-based devices for diverse applications. Finally, the challenges and future opportunities for Se nanostructures and Se-related devices are also discussed.

Two-dimensional (2D) materials, such as transition metal dichalcogenides (TMDs), black phosphorus (BP), MXene and borophene, have aroused extensive attention since the discovery of graphene in 2004. They have wide range of applications in many research fields, such as optoelectronic devices, energy storage, catalysis, owing to their striking physical and chemical properties. Among them, anisotropic 2D material is one kind of 2D materials that possess different properties along different directions caused by the intrinsic anisotropic atoms' arrangement of the 2D materials, mainly including BP, borophene, low-symmetry TMDs (ReSe 2 and ReS 2) and group IV monochalcogenides (SnS, SnSe, GeS, and GeSe). Recently, a series of new devices has been fabricated based on these anisotropic 2D materials. In this review, we start from a brief introduction of the classifications, crystal structures, preparation techniques, stability, as well as the strategy to discriminate the anisotropic characteristics of 2D materials. Then, the recent advanced applications including electronic devices, optoelectronic devices, thermoelectric devices and nanomechanical devices based on the anisotropic 2D materials both in experiment and theory have been summarized. Finally, the current challenges and prospects in device designs, integration, mechanical analysis, and micro-/nano-fabrication techniques related to anisotropic 2D materials have been discussed. This review is aimed to give a generalized knowledge of anisotropic 2D materials and their current devices applications, and thus inspiring the exploration and development of other kinds of new anisotropic 2D materials and various novel device applications.