Real‐time terahertz meta‐cryptography using polarization‐multiplexed graphene‐based computer‐generated holograms

Abstract As one of the cutting‐edge technologies in advanced information science, wave‐based cryptography is a prerequisite to enable a plethora of secure encrypting platforms which can be realized by smart multiplexing techniques together with suitable metasurface holograms (meta‐holograms). Here, relying on the polarization multiplicity and re‐writability of a computer‐generated meta‐hologram, a fully secure communication protocol is elaborately developed at the terahertz spectrum to host unique merits for exploring real‐time metasurface‐based cryptography (meta‐cryptography) where highly restricted access of information is imposed. The proposed meta‐cryptography exploits two dynamic near‐field channels of a meta‐hologram whose information can be instantaneously re‐written without any polarization rotation and with high contrast and acceptable frequency bandwidth. The computer‐generated meta‐hologram is constructed based on the weighted Gerchberg–Saxton algorithm…