Optical architectures for information processing: advances in pattern recognition, phase imaging, and image encryption.

Optical information processing is a powerful paradigm due to its inherent parallelism, high speed, and multidimensional processing capability. This study provides a comprehensive overview of optical architectures for information processing, with particular focus on optical pattern recognition, phase retrieval techniques, and optical security frameworks. Optical correlators are among the most significant implementations of optical information processing for pattern recognition. They can correlate vast amounts of data simultaneously by exploiting the inherent parallelism of light, enabling processing at the speed of light. The unparalleled computational capability surpasses the performance limits of conventional electronic processors, making optical correlators highly suitable for real-time and high-throughput pattern recognition applications. Various parameters of the optical field provide distinctive and versatile means to encode information. Properties such as amplitude, phase, polarization, wavelength, and orbital angular momentum enable multidimensional data representation, thereby enhancing encoding capability, security, and transmission efficiency. Further, optical imaging techniques have advanced significantly, delivering improved resolution, contrast, and functional imaging capabilities. A significant contribution to this progress comes from phase retrieval techniques, which reconstruct phase information from intensity-only measurements. Collectively, these approaches demonstrate the potential of hybrid optical-digital systems for next-generation imaging and information processing applications.