Multi‐Channel Metasurface for Versatile Wavefront and Polarization Manipulation

Metasurfaces are extensively studied for the flexible manipulation of wavefront and polarization of electromagnetic waves with significant merits such as ultra‐thin profiles and low insertion losses. However, conventional meta‐devices are usually limited by achieving only single polarization modulation, and it is challenging to achieve mixed polarization and wavefront manipulation in a single metasurface. Here, a single‐layer anisotropic metasurface for independent wavefront manipulation in multiple polarization channels is presented. The meta‐atom is composed of two orthogonal dumbbell‐shaped metal patches placed on the top of a dielectric layer with grounded plane on the bottom. The reflective phases of the two orthogonal linearly polarized waves can be independently manipulated by changing the dimensions of the dumbbell‐shaped resonator. As a result, not only the propagation phase but also the polarization state of the outgoing wave can be manipulated independently as desired. As proof of concept, a metasurface is designed for converging the reflection beams of four polarization states to specific positions for four‐focus holographic imaging. The measured results are in good agreements with simulated ones, verifying the independent wavefront manipulations with arbitrary polarization conversions.