Polarization-Encoded Fully-Phase Encryption Using Transport-of-Intensity Equation

• Main Authors: Alok K. Gupta, Praveen Kumar, Naveen K. Nishchal, Ayman Alfalou
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Electronics
• Subjects: optical encryption; transport of intensity equation; spatially variant polarized beam; phase-only information
• Online Access: https://www.mdpi.com/2079-9292/10/8/969

In this study, we propose a novel method to encrypt fully-phase information combining the concepts of the transport of intensity equation and spatially variant polarization encoding. The transport of intensity equation is a non-iterative and non-interferometric phase-retrieval method which recovers the phase information from defocused intensities. Spatially variant polarization encoding employs defocused intensity measurements. The proposed cryptosystem uses a two-step optical experimentation process—primarily, a simple set-up for defocused intensities recording for phase retrieval and then a set-up for encoding. Strong security, convenient intensity-based measurements, and noise-free decryption are the main features of the proposed method. The simulation results have been presented in support of the proposed idea. However, the TIE section of the cryptosystem, as of now, has been experimentally demonstrated for micro-lens.