Holographically marked metasurface towards multi-user authentication

Metasurface-based image encryption is becoming an increasingly prevalent trend in optical security; yet, limited attention has been directed towards metasurface-based image authentication. Here, we present a holographically marked metasurface for multi-user authentication based on polarization multiplexing technology. Through embedding a holographic marker in the metasurface via a different polarization channel, it simplifies the distinction between different metasurfaces, while simultaneously achieving multi-user authentication. In the authentication process, only by applying the correct authentication keys to the metasurface can the verifiable images be reconstructed. Computer simulation results confirm the feasibility and security of the proposed metasurface-based security approach.