Seeing through randomness with topological light

Abstract

Transmitting structured light robustly through complex random media is crucial in many applications, from sensing to communication. Unfortunately, the spatial structure of light is distorted in such media due to refractive index inhomogeneities that cause multiple scattering, requiring mitigating strategies such as iterative optimisation and adaptive optics. Here, we use topological light to see through random media without the need for any corrective measures. Using skyrmions as our optical topology, we first demonstrate their robustness to randomness using controlled digital random phase masks before showing the universality of the approach with physical samples, from biological tissue to highly scattering materials. We benchmark the invariance of the topology against orbital angular momentum (OAM) and show no modal crosstalk using topology in channels where orbital angular momentum exhibits crosstalk greater than 70%. With the control in hand, we transmit images encoded into an alphabet of 10 topological numbers and show information transfer with high fidelity in regimes where traditional degrees of freedom, such as OAM, fail. Our work represents an important step towards noise-free transmission through noisy channels with the spatial structure of light without the need for active compensation strategies, opening potential applications in imaging, sensing and communicating with topology.