Abstract
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.