Spin‐Decoupled Metasurface by Hybridizing Curvature‐ and Rotation‐Induced Geometrical Phases

Abstract Geometric phases are very important for achieving broadband functional metasurfaces, which are usually obtained by rotating meta‐atoms. However, such rotation‐induced geometric phases are inherently spin‐coupled, with the same magnitude and opposite sign for left‐ and right‐handed circularly polarized (LCP and RCP) waves, which is unfavorable for designing different functions for LCP and RCP waves. Therefore, it is desirable that geometric phases for single circular polarization be explored. In this work, it is first proposed to achieve geometric phases for single polarization by delicately designing curvature of the meta‐atom, which only imparts geometric phase to RCP or LCP waves. Then, spin‐decoupled metasurfaces are designed by hybridizing such curvature‐induced geometric phases and conventional rotation‐induced geometric phases. Two prototypes of dual‐channel functional metasurfaces are designed, fabricated, and measured. Both the simulated and experimental results verify the spin‐decoupled phase modulation. This work expands the methods of phase engineering in metasurfaces and may find wide applications in communication, sensing, imaging, and others.