Negative refractive index metamaterials in the visible spectrum based on MgB2∕SiC composites

An isotropic three-dimensional negative refractive index metamaterial has been fabricated and characterized in the visible regime. The metamaterial is based on a structure consisting of polycrystalline magnesium diboride (MgB2) as the host, providing negative permittivity, and silicon carbide (SiC) nanoparticles embedded randomly within the host, providing negative permeability. The metamaterial was fabricated using hot isostatic pressing to produce a fully dense solid with well-dispersed SiC nanoparticles. The properties of the resulting bulk metamaterial were evaluated using surface plasmon excitation, which showed coupling of both magnetic and electric plasmons, signifying both negative permeability and permittivity at 632nm.