Metamaterials for high-performance photodetectors

Metamaterials, a kind of novel materials with artificial design, have exhibited extraordinary properties that cannot be found in nature. In the past decade, remarkable achievements have been made in the field of metamaterial-based photodetectors. However, there is hardly any systematic and thorough review of the metamaterials' recent development in photodetection devices. Herein, we summarized recent advances in the metamaterial-based photodetectors according to a dual role of metamaterials: enrichment of photodetection functionalities and enhancement of photodetection performance. To start with, we presented an overview of the relevant concept of metamaterials and explore their distinctive optical characteristics. Subsequently, we delved into the work mechanism and figures of merit of metamaterial-based photodetectors. Next, we highlighted various types of metamaterials as a flexible platform for advanced photodetection technology, including metasurface, graphene-metamaterial hybrids, patterned nanostructures, and van der Waals metamaterials. Finally, the challenges and outlook associated with future developments were systematically and deeply discussed based on the current state of research. We believe that this review will offer crucial insights and valuable guidance, paving the way for future advancements and in-depth investigations in the realm of metamaterial-based photodetectors.