Optical multiple information hiding via azimuth multiplexing

Abstract We propose an optical information hiding scheme based on azimuth multiplexing. Azimuth is first introduced into optical information security, which effectively improves the space utilization. Also, the security of the system is ensured in many aspects because of the combination of free-space optics and visual cryptography. In the hiding process, multiple secret messages are encoded by visual cryptography and hidden in a cascaded phase structure of different azimuthal states. When extracting, different information can be extracted by rotating pure phase masks to a specific azimuth. The simulations and analysis also demonstrate that the system is robust to common perturbations, such as noise and blocking.