Optical information hiding with non-mechanical ptychography encoding

Abstract Since the ptychographic encoding can transform the secret information into series of diffractive patterns optically, it achieves the high security for information hiding. However, traditional ptychographic encoding requires the mechanical movements of the illuminated probe or the hidden object, which accumulates the errors greatly reducing the decoding quality. The errors have been reduced with the way of the single-shot ptychographic encoding, while its reliability and the decoding quality are still unideal. To solve these problems, we propose a non-mechanical ptychography to hide optical information for the first time. The core of this method includes both the non-mechanical ptychographic encoding (NPE) via a spatial light modulator and the decoding algorithm constrained with the phase-only quick respond code (PQR). NPE completely eliminates the errors arising from the ptychographic scanning, and the PQR-constrained decoding algorithm enables the high-quality information extracted from even only a few embedded diffractive patterns. The optical experiments verify that the method can achieve satisfactory robustness performance with the high repeatability, real-time encoding speed and the excellent information fidelity.