Polarization-independent 1-bit programmable near-field amplitude imaging metasurface with XOR encryption for secure...

To resolve the contradiction between the susceptibility of amplitude imaging to information leakage and the implementation complexity of phase imaging technology in metasurface imaging, this paper proposes a polarization-independent 1-bit programmable near-field amplitude imaging metasurface based on liquid crystal, and combines the XOR encryption algorithm to enhance information security. Numerical simulations demonstrate that the proposed metasurface possesses outstanding polarization independence and angular insensitivity within the frequency range of 79.7-92.6 GHz. Additionally, successful imaging of the characters "X," "H," "F," "U," and "T" is achieved, with optimal image resolution attained at a distance of 0.75 mm from the metasurface. The XOR algorithm can generate ciphertext images by performing a bitwise operation on the plaintext and the key, and the same key can restore the plaintext. Notably, "HFUT" can be disguised as "ECNU" to enhance concealment. This design balances imaging quality and information security, offering a promising approach for the application of metasurfaces in secure communication.