Array of vector vortex beam for audio security

Abstract Structured light beams, particularly vector vortex beams, have gained significant attention for secure high-capacity data encoding due to their spatially varying polarization and associated orbital angular momentum. These beams theoretically offer access to an infinite set of orthogonal modes, enabling parallel information transfer, robust encryption, and enhanced data security. Of late, audio encryption has become increasingly essential in domains such as confidential communication, artificial intelligence-driven voice forensics, and corporate voice protection. The traditional encryption methods—both digital and optical, suffer from drawbacks like high computational demands, alignment sensitivity, and poor real-time performance. To address these limitations, we propose an audio encryption scheme employing an array of vector vortices integrated with digital holography. The audio signal is first captured using parallel phase-shifting digital holography (PPSDH) and then multiplexed into a structured array of vector vortex beams. This approach encodes the signal into the intensity of the light beam, allowing decoding through simple intensity-based measurements. Additionally, combining actual audio with random data during encoding enhances security against unauthorized access. The holographic recording supports capturing audio signals at various three-dimensional (3D) spatial positions, enabling 3D voice encryption. The PPSDH technique further allows single-frame acquisition, making the method well-suited for dynamic signal encoding. This compact and efficient approach offers a real-time, secure optical encryption method for audio signals, provided that a suitable processor is used for timely computational execution.