Breaking order: Talbot effect with spinodal architectures
The Talbot effect describes the emergence of periodic patterns in perturbed propagating wave fields. The effect is well studied for perturbations from structurally coherent optics such as diffraction gratings. The emergence of freeform and metaoptical designs raises the question of whether comparable behavior can also be observed from complex, non-periodic structures. Here we demonstrate that stochastic structures inspired by recent metamaterial designs, display a strong Talbot-like behavior. Re-emergence of projected wavefronts through stochastic spinodal architectures at distinct propagation distances are proven theoretically and experimentally in the visible and hard X-ray regimes. A direct application of this phenomenon is X-ray dark-field imaging for characterizing artificial and natural meso-structured materials. Our work shows that spinodal X-ray optics effectively bridge the gap between the two opposing approaches in dark-field X-ray imaging that advocate for either spatially fully coherent (i.e gratings) or incoherent (i.e diffusers) optics. This opens opportunities for exploring a new dimension in the implementation of X-ray imaging methods. Given the impact and universality of the classical Talbot effect, we expect our work to enable new opportunities for characterizing and manipulating matter.