E‐Band Metasurface‐Based Orbital Angular Momentum Multiplexing and Demultiplexing

Abstract

Abstract Orbital angular momentum (OAM) has received considerable attention regarding high‐capacity communication owing to its spatial orthogonality. However, it is still challenging to build a compact communication system that can generate multiple coaxial OAM beams and receive information from each. In this work, OAM multiplexing and demultiplexing at the E‐band frequency using a single metasurface structure is proposed and experimentally demonstrated. For OAM multiplexing, the metasurface used as a transceiver generates two orthogonal coaxial OAM beams for Gaussian incident beams with different incidence angles. For OAM demultiplexing, the same metasurface flipped 180° as a receiver forms a Gaussian beam in different off‐axis directions depending on the topological charge of the coaxially incident OAM beam. The Gaussian beam measured at the receiver end exhibits a high signal‐to‐noise ratio of more than 33 dB compared with the background OAM beam. OAM multiplexing and demultiplexing based on a single metasurface may provide a route for high‐capacity and compact free‐space communication systems.