Reconfigurable metasurface for code division multiplexing high-capacity and low-crosstalk holographic encryption

Metasurface multiplexing holography shows potential to enhance information capacity but faces challenges such as crosstalk and limited dynamic switching. Leveraging the orthogonality of code division multiplexing (CDM) technology, we propose a reconfigurable metasurface-based encryption scheme. Here, the CDM code acts as a decryption key, enabling dynamic holographic image switching and ensuring secure information transmission. The circular polarization information is encoded into the reconfigurable metasurface using simultaneous modulation of geometric and propagation phases. By controlling polarization states of incident light and crystallization levels of GSST, the high-capacity and low-crosstalk CDM holographic images can be generated. Furthermore, a detailed analysis is conducted on the capacity of CDM holography, the factors influencing the efficiency of metasurface diffraction, and the scalability and feasibility of practical manufacturing. This proposed scheme has the ability to significantly boost encryption security, paving the way for increased information storage capacity and optical encryption.