Design of a Reconfigurable Metasurface for Holograms in Full-space

Metasurfaces have gained significant attention due to their compact dimensions, while reconfigurable metasurface arrays are widely employed for their multifunctional capabilities. Although full-space electromagnetic manipulation can be achieved by controlling different layers in a reconfigurable metasurface, the feasibility of realizing full-space electromagnetic control through ON/OFF switching of the loaded diodes within the same metasurface layer remains an open question. In this work, a reconfigurable unit is proposed, where four diodes are controlled to achieve 1-bit phase variation in both reflection and transmission modes. Utilizing this tunable unit, we demonstrate lens focusing, multi-focus focusing, and full-space holographic imaging of the letters 'E', 'C', 'N', and 'U'. The proposed reconfigurable unit and holographic images may serve as a potential solution for future intelligent devices in applications such as display, data storage, and information processing.