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Owing to their extraordinary physical and chemical properties, two-dimensional (2D) materials have aroused extensive attention and have been widely used in photonic and optoelectronic devices, catalytic reactions, and biomedicine. In particular, 2D materials possess a unique bandgap structure and nonlinear optical properties, which can be used as saturable absorbers in ultrafast lasers. Here, we mainly review the top-down and bottom-up methods for preparing 2D materials, such as graphene, topological insulators, transition metal dichalcogenides, black phosphorus, and MXenes. Then, we focus on the ultrafast applications of 2D materials at the typical operating wavelengths of 1, 1.5, 2, and 3 μm. The key parameters and output performance of ultrafast pulsed lasers based on 2D materials are discussed. Furthermore, an outlook regarding the fabrication methods and the development of 2D materials in ultrafast photonics is also presented.

Nanomaterials with remarkable optical, mechanical, and electrical properties have shed new light on various fields including optoelectronics, sensors, biomedicine, and ultrafast photonics. Particularly, owing to their nonlinear optical properties, fast recovery time, and broadband operation, nanomaterials are well qualified as saturable absorbers in ultrafast pulsed lasers. Over the development of the past decades, various nanomaterials have been developed as saturable absorbers, which contribute to a diversity of lasers with excellent performance. Therefore, it is important for researchers to provide a landmark of the applications of nanomaterials in ultrafast photonics concerning cutting‐edge development. Herein, the integration and applications of nanomaterials in ultrafast photonics are reviewed. First, end‐face, lateral, as well as photonic crystal fibers padding integration methods are introduced along with their process and characteristics. Then the ultrafast applications of nanomaterials including carbon‐based (carbon nanotubes and graphene), typical 2D (topological insulators, transition metal dichalcogenides, black phosphorus, and MXenes), and metal‐based nanomaterials (gold, silver, copper, and metal oxides) are summarized. Major parameters of ultrafast lasers and features of each nanomaterial are presented simultaneously. Finally, the perspectives of nanomaterials for further development in ultrafast photonics are discussed.

The rapid expansion of nanotechnology and material science prompts two-dimensional (2D) materials to be extensively used in biomedicine, optoelectronic devices, and ultrafast photonics. Owing to the broadband operation, ultrafast recovery time, and saturable absorption properties, 2D materials become the promising candidates for being saturable absorbers in ultrafast pulsed lasers. In recent years, the novel 2D MXene materials have occupied the forefront due to their superior optical and electronic, as well as mechanical and chemical properties. Herein, we introduce the fabrication methods of MXenes, incorporation methods of combining 2D materials with laser cavities, and applications of ultrafast pulsed lasers based on MXenes. Firstly, top-down and bottom-up approaches are two types of fabrication methods, where top-down way mainly contains acid etching and the chief way of bottom-up method is chemical vapor deposition. In addition to these two typical ones, other methods are also discussed. Then we summarize the advantages and drawbacks of these approaches. Besides, commonly used incorporation methods, such as sandwich structure, optical deposition, as well as coupling with D-shaped, tapered, and photonic crystal fibers are reviewed. We also discuss their merits, defects, and conditions of selecting different methods. Moreover, we introduce the state of the art of ultrafast pulsed lasers based on MXenes at different wavelengths and highlight some excellent output performance. Ultimately, the outlook for improving fabrication methods and applications of MXene-based ultrafast lasers is presented.

Ultrafast Photonics Nanomaterials with remarkable optical properties including carbon‐based, typical two‐dimensional, and metal‐based nanomaterials have been widely used in ultrafast photonics over the years. In article number 2200386, Bo Fu, Han Zhang, and co‐workers review the ultrafast applications, typical parameters of ultrafast lasers, features of each nanomaterial, and further development in ultrafast photonics.