Graphene-based metasurface: dynamic optical control in ultrathin flat optics.

Graphene hosts massless Dirac fermions owing to its linear electronic band structure. This distinctive feature underpins its extraordinary electronic properties, correlating to strong light-matter interactions on an extreme subwavelength scale. Over the past decade, intensive investigations have transitioned from fundamental graphene's optical properties to practical application with the integration of graphene into metasurfaces, opening a new era of active flat optics. In this review, we provide a comprehensive overview of graphene-based metasurfaces, beginning with the intrinsic link between graphene's optical response and its electronic properties. We highlight the development of actively tunable platforms and devices, including efficient modulators, high-sensitivity detectors, and advanced biosensing systems. We also discuss emerging approaches that enable ultrafast all-optical modulation and ultracompact device footprints, pushing the boundaries of performance. Finally, we explore the transformative prospects of non-Hermitian physics and inverse design strategies as novel frameworks for optimizing metasurface configurations. By synergizing graphene's intrinsic tunability with innovative design methodologies, graphene-based metasurfaces hold immense potential to bridge the gap between fundamental science and real-world applications, defining a new frontier in next-generation photonic technologies.