Optical multi-image encryption based on focal length multiplexing and multimode phase retrieval.

Abstract

A novel optical multi-image encryption method based on focal length multiplexing and multimode phase retrieval is proposed in this study. During the encryption process of the proposed method, multiple secret images were encrypted into a single intensity-only image using focal length multiplexing and a coherent diffractive imaging-based encryption system. A specially designed iterative algorithm based on multimode phase retrieval is proposed for the accurate decryption of the original multiple secret images from the intensity pattern. The advantages of the proposed method include a compact optical setup and high decryption quality. The feasibility, security, and robustness of the proposed method were investigated by numerical simulations.