Unlocking metamaterial properties through multiscale design

Extraordinary electromagnetic behaviour, such as negative refractive index, can be produced in metamaterial com- posites. A number of impressive specimens have been produced to date, though they typically rely on conductor inclusions with intricate topologies, or dielectric inclusions with very high permittivity. We show that by designing the composite on two di erent length scales, we are able to bring about metamaterial behaviour using quite simple constituent materials and topologies. One scale is analyzed in the long wavelength limit, where metallic (or otherwise conducting) nanoparticles are mixed into a common dielectric phase, producing material with a high, and tunable, permittivity. This material is then used as the inclusion in the larger scale, where the high permittivity produces electric and magnetic Mie resonances, leading to a negative refractive index of the composite as a whole.