Research on optical encryption system based on unequal modulus decomposition and polarized vortex optical holography

In this paper, we present an optical encryption system which uses the principle of unequal modulus decomposition and polarization vortex optical holography to implement encoding and decoding. Firstly, the original image is decomposed into two complex amplitude images by unequal modulus decomposition method, then their polarization states are changed by vortex beams irradiation, and finally they are encrypted in the photorefractive crystals by polarization multiplexing holographic technology. In decryption, the image can be reconstructed successfully when a series of correct keys are provided. The sensitivity of polarization state and the multiplexing performance of topological charge are also analyzed, proving the method has high security. •The image is encrypted by recording the polarization state of the beam.•The use of SPL and random amplitude masks can further enhance encryption strength.•White Noise analysis shows that the proposed method has high security.