Fig. 5: Proof-of-concept experimental demonstration of optical information encryption.
From: Broadband generation of perfect Poincaré beams via dielectric spin-multiplexed metasurface
a The plaintext message including a set of complex account number and password composed of different characters (left) are translated into the combinations of hexadecimal numbers (right) by User 1. b The design parameters of the 25 PPBs (left) and SEM image of a portion of the metasurface termed ciphertext (right). Scale bar: 500 nm. c User 2 captures two images with the two customized keys. According to the code chart, the first and second digits of these two-digit hexadecimal numbers are decrypted by User 2, respectively. Scale bar: 50 μm. d The hexadecimal number combination is decrypted as the plaintext message including the account number and password based on the ASCII.
