Fundamentals and Applications of Metasurfaces

TLDR

Metasurfaces are a rapidly growing research area due to their exceptional light‑manipulation capabilities, ultrathin optical applications, simplified fabrication compared to metamaterials, and planar profiles that enable on‑chip nanophotonic integration. This review surveys recent progress in metasurfaces and classifies them into six physics‑based categories for achieving full 2π phase manipulation. The authors describe multi‑resonance and gap‑plasmon metasurfaces that exploit plasmonic nanoantenna geometry, Pancharatnam–Berry‑phase metasurfaces that use rotating nanoantennas, state‑of‑the‑art fabrication methods ranging from electron‑beam to nanoimprint lithography, and functional materials for reconfigurable or tunable metasurfaces. The review highlights that Huygens' and all‑dielectric metasurfaces enable highly efficient transmission, and it discusses several intriguing applications while outlining future prospects.

Abstract

Metasurfaces have become a rapidly growing field of research in recent years due to their exceptional abilities in light manipulation and versatility in ultrathin optical applications. They also significantly benefit from their simplified fabrication process compared to metamaterials and are promising for integration with on‐chip nanophotonic devices owing to their planar profiles. The recent progress in metasurfaces is reviewed and they are classified into six categories according to their underlying physics for realizing full 2π phase manipulation. Starting from multi‐resonance and gap‐plasmon metasurfaces that rely on the geometric effect of plasmonic nanoantennas, Pancharatnam–Berry‐phase metasurfaces, on the other hand, use identical nanoantennas with varying rotation angles. The recent development of Huygens' metasurfaces and all‐dielectric metasurfaces especially benefit from highly efficient transmission applications. An overview of state‐of‐the‐art fabrication technologies is introduced, ranging from the commonly used processes such as electron beam and focused‐ion‐beam lithography to some emerging techniques, such as self‐assembly and nanoimprint lithography. A variety of functional materials incorporated to reconfigurable or tunable metasurfaces is also presented. Finally, a few of the current intriguing metasurface‐based applications are discussed, and opinions on future prospects are provided.