UNSEEN · Nanostructure-Based Design of Visual Perception using High-Index Disordered Metasurface Physics

The optics of disordered media with subwavelength high-contrast resonant inhomogeneities is a fascinating research topic emerging at the interface between the physics of waves in complex media and nanophotonics. UNSEEN explores and exploits unconventional wave-interference phenomena in disordered metasurfaces towards a new application: the creation of brand-new visual appearance.Our perception of objects is completely determined by how they scatter light. Color is crucial, but other attributes, such as texture, gloss for reflective surfaces, clarity for transmissive ones, illumination directivity also largely influence appearance. Although this perception plays a key role in virtually all fine and applied arts, appearance engineering has been so far applied only to materials structured at length scales significantly larger than the wavelength; this is because the link between nanostructure morphologies and appearance is very complicated for subwavelength scale resonant inhomogeneities.UNSEEN bridges, for the first time, the fertile environments of optical metasurfaces and visual appearance in an original and cross-disciplinary way. At the forefront of optical modelling and characterization, we will develop new tools in nanophotonics, which will merge nanoscale electromagnetism, mesoscale multiple scattering, and macroscale ray-tracing rendering. The tools will allow us to understand the complicated relation between morphology and appearance, to harness the manifold degrees of freedom offered by disordered metasurfaces and to discover clues to design novel appearance. We will then use available state-of-the-art nanofabrication and develop new characterization setups to produce and observe metasurfaces with novel appearances, and further study their most promising applications: luxury goods, document security, and head-up display.