Revealing the invariance of vectorial structured light in complex media

Optical aberrations have been studied for centuries, placing fundamental limits on the achievable resolution in focusing and imaging. In context of structured light, spatial pattern is distorted amplitude phase, often arising from optical imperfections, element misalignment, or even dynamic processes due to propagation through perturbing media such as living tissue, free-space, underwater fibre. Here we show that polarisation inhomogeneity defines vectorial light immune all perturbations, provided they are unitary. By way example, study robustness vector vortex beams tilted lenses atmospheric turbulence, both highly asymmetric aberrations, demonstrating inhomogeneous nature remains unaltered near-field far-field, structure itself changes. The unitary channel allows us undo this change a simple lossless operation, tailoring appears robust its regardless medium. Our insight highlights overlooked role measurement describing classical fields, doing so resolving prior contradictory reports complex media. This paves versatile application non-ideal systems, crucial applications imaging deep into tissue communication across noisy channels.