Spatial multiplexing encryption with cascaded metasurfaces

Abstract Recent years have witnessed rapid progresses in information encryption by harnessing different dimensions of light, yet, pushing the capacity of encrypted information is an endless goal. Meta-holographic encryption introduces an efficient method in optical information encryption. Here, we propose a spatial multiplexing encryption technique using cascaded metasurfaces, allowing multiple users to simultaneously access independent encryption information. By employing cascaded metasurfaces, cipher images and corresponding decryption keys can be transferred to unique spatial hologram coordinates for each user, ensuring secure identification of encrypted information. We demonstrate the feasibility of six encrypted channels and analyze the sensitivity to holography spatial location, revealing a low correlation among different channels. Our findings highlight the potential of cascaded metasurfaces in spatial multiplexing encryption, paving the way for high-volume optical information encryption.