Optical Topological Differentiation Cryptography

ABSTRACT Optical encryption provides an effective way to secure confidential information, featuring low energy consumption, parallel operation, high speed, and the ability to process multidimensional data. However, a unified framework that can encrypt and decrypt optical information across the fundamental spatial physical dimensions (amplitude, phase, and polarization) is still lacking. Here, we present an optical cryptography approach based on topological differentiation via Pancharatnam–Berry (PB) phase liquid crystal optical elements. By leveraging the spin‐dependent phase modulation of the PB phase, binary‐encoded optical images in any physical dimension are encrypted into an identical ciphertext, effectively hiding the information by converting it into edge‐based representations. Decryption is accomplished through a conjugate topological differentiation operation, which precisely reverses the process by redistributing energy from the edge back to the center, thereby restoring the original image. As a proof of concept, we successfully demonstrated the encryption and decryption of the plaintext information “LIGHT” across the spatial dimensions of amplitude, phase, and polarization. This work introduces a new paradigm in optical information security by innovatively applying optical differentiation to physical‐layer encryption and decryption, providing a robust and unified approach for the protection of multidimensional optical data.