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 via a two-dimensional array of vertical graphene strips whose anisotropic reflection is merely determined by external biasing conditions. Several illustrative examples have been presented to demonstrate the perfect secrecy and polarization cross-talk of the proposed meta-cryptography. Numerical simulations corroborate well our theoretical predictions. As the first demonstration of dynamic THz meta-cryptography, the meta-hologram information channels can be deciphered into manifold customized messages which would be instrumental in data storage systems offering far higher data rates than electronic encryption can deliver.

中文翻译：

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使用基于极化多路复用石墨烯的计算机生成全息图的实时太赫兹元密码学

摘要 作为先进信息科学的前沿技术之一，基于波的密码学是实现大量安全加密平台的先决条件，这些平台可以通过智能复用技术和合适的超表面全息图（meta-holograms）实现。在这里，依靠计算机生成的元全息图的极化多重性和可重写性，在太赫兹光谱上精心开发了一种完全安全的通信协议，以提供探索实时基于超表面的密码学（元密码学）的独特优点信息访问受到严格限制的地方。所提出的元密码术利用元全息图的两个动态近场通道，其信息可以在没有任何偏振旋转的情况下即时重写，并且具有高对比度和可接受的频率带宽。计算机生成的元全息图是基于加权 Gerchberg-Saxton 算法通过垂直石墨烯条的二维阵列构建的，其各向异性反射仅由外部偏置条件决定。已经提出了几个说明性的例子来证明所提出的元密码术的完美保密和极化串扰。数值模拟很好地证实了我们的理论预测。作为动态太赫兹元密码学的首次演示，