Macroscopic Self‐Assembly and Optical Characterization of Nanoparticle–Ligand Metamaterials

A self-assembled metamaterial exhibiting a positive near-zero index of refraction at visible wavelengths is demonstrated. The metamaterial consists of thiolene-functionalized gold nanospheres self-assembled into macroscopic, crosslinked, monolayers. By measuring the real and imaginary parts of the phase shift of light transmitted through the self-assembled films the effective index of refraction is determined as a function of wavelength. These findings may pave a way to simply and efficiently self-assemble and optically characterize multifunctional, multilayer nanoparticle-ligand metamaterials.