Dynamically Tunable Deep Subwavelength High-Order Anomalous Reflection Using Graphene Metasurfaces

Graphene-based metasurfaces have emerged as promising photoelectric devices that can dynamically control the behavior of electromagnetic waves. The high-order anomalous reflection provides an additional degree of freedom in the field of photonic research. Here, a series of gradient graphene metasurfaces with high-order modes to manipulate the wavefront of reflected light is proposed. By properly arranging the graphene nanostructures, 5-order anomalous reflection and 15-order high-quality Laguerre-Gaussian beams are achieved. Furthermore, the efficiency of the metasurfaces is dynamically controlled by tuning the electrostatic gating to change the Fermi energy of graphene. This work offers a new idea for the development of tunable wavefront-controlling devices and contributes to a wide range of applications in photonic systems.