Independent Manipulation of Aperture and Radiation Fields in a Transmission-Reflection Integrated Complex-Amplitude Metasurface

Metasurfaces have superior performance in flexible wave manipulation used for various multifunctional devices. However, they remain challenging for the completely spatial manipulation of electromagnetic waves including wave propagation direction and distance degrees of freedom. Here, a novel strategy of multiplexing metasurface with a non-interleaved meta-atoms array is introduced. The design fully explores wave propagation direction and distance degrees of freedom by combining irregular complex-amplitude encoding method and transmission-reflection selective meta-atom. Therein, by limiting effective meta-atoms to a specific geometry and encoding highly selective phase sequences for wavefront shaping to these meta-atoms, the distance multiplexing properties of aperture and radiation fields can be designed to suit application needs. Also, the transmission-reflection integrated meta-atoms is further engineered to increase the propagation direction degrees of freedom in electromagnetic manipulation. As proof of concept, a six-channel metasurface operating in one transmitted mode and two reflected modes are experimentally generated, enabling us to reconstruct an aperture-field printing image and a radiation-field holographic image for each mode simultaneously. This strategy may have an alternative route for potential applications such as data storage, image encryption, and information communication systems.