Electromagnetic Diffusion and Encryption Holography Integration Based on Reflection-Transmission Reconfigurable Digital Coding Metasurface

The integration of different functionalities into a real-time reconfigurable metasurface can give it more powerful ability in manipulation of electromagnetic (EM) waves. Here, a reflection-transmission (R-T) reconfigurable digital coding metasurface, which can be flexibly switched between the reflection and transmission working states with the completely different functions, is proposed and demonstrated. As a proof of concept, an R-T reconfigurable metasurface with integrated functions of EM diffusion in reflection state and encryption holography in transmission state is designed and demonstrated. The results have been validated by both numerical simulations and experimental measurements, showing that the proposed R-T reconfigurable metasurface can be real-timely controlled to work in reflection state or transmission state by adjusting bias voltage, in which the incident EM waves are totally reflected and randomly diffused to achieve low radar cross section (RCS) in reflection state and efficiently transmitted to realize encrypted holographic images in transmission state.