Résumé
Optical metasurfaces are two-dimensional assemblies of nanoscale optical resonators and could constitute the next-generation of ultra-thin optical components. The development of methods to manufacture those nanostructures on a large scale is still a challenge, while most performance demonstrations were obtained with lithographically fabricated metasurfaces, that are restricted to small scales. Self-assembly fabrication routes are scattering of the nanoresonators in a meta-fluid, and show that they present strong optical magnetic resonances and directional forward scattering patterns, with scattering efficiencies of up to 4. The metasurfaces consist in homogeneous films, of variable surface density, of colloidal clusters which have the same extinction properties on the surface and in the fluid. This experimental approach allows for the large scale production of metasurfaces.