MXenes: synthesis, incorporation, and applications in ultrafast lasers

Abstract

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.

Fabrication and Applications of Heterostructure Materials for Broadband Ultrafast Photonics

“…[51][52][53] MXenes also exhibit outstanding optical properties such as high output power, ultra-wide operating band, and tunable band-gap. [54][55][56][57] However, BP and MXenes both have the shortcoming of instability because they are easily oxidized. [58,59] Metal nanomaterials, such as gold nanoparticles and silver nanoparticles have the unique third-order optical nonlinearity, owing to the surface plasmon resonance.…”

Integration and Applications of Nanomaterials for Ultrafast Photonics

“…[48,49] MXenes exhibit tunable bandgap, large nonlinear absorption coefficient, as well as broadband optical response which enlarges its applications in ultrafast photonics. [50][51][52][53] In addition, as for pure metal nanomaterials such as gold (Au), silver (Ag), and copper (Cu) nanoparticles, the unique surface plasmon resonance (SPR) effect which is formed by the interaction between the conduction electrons and electric fields, [17,54,55] endows the metal nanomaterials with the excellent third-order nonlinear property. Metal oxides have the advantage of tunable bandgap and affordability.…”

Recent Advances and Challenges in Ultrafast Photonics Enabled by Metal Nanomaterials

“…[58][59][60] It can be attributed to their outstanding properties such as excellent conductivity, tunable bandgap, and large nonlinear absorption coefficient on the order of 10 -2 to 10 -1 cm GW -1 as well as the imaginary part of the thirdorder nonlinear optical susceptibility on the order of 10 -13 esu and greater. [21,[61][62][63][64][65] However, the oxidation stability in air and inclination for self-restacking restrict their applications. [58,66,67] Metal nanomaterials have aroused extensive interests owing to their interesting characteristic called surface plasmon resonance (SPR).…”