Unlocking Secure Optical Multiplexing with Spatially Incoherent Light

While coherent light holds promise for optical multiplexing via orthogonal degrees of freedom, its vulnerability to disturbances often results in information loss and retrieval hurdles, primarily due to its reliance on first-order optical parameters. Herein, an incoherent optical information multiplexing and retrieval protocol is proposed theoretically and verified experimentally by harnessing the two-point field correlations of structured random light. The optical information is securely stored in the multiplexed field correlations which are inaccessible to a direct capture by a camera and retrieved only through rigorous statistical processing. The inherently incoherent nature of random waves makes this protocol crosstalk-free in principle and guarantees its high fidelity even in an extremely noisy environment. The advanced protocol opens new horizons in an array of fields, such as optical cryptography and optical imaging, and it can be relevant for information processing with random waves of diverse physical nature, including acoustic and matter waves.