Anisotropic metallic metasurface superlattices supporting Fano resonances and bound states in the continuum

A perfect metal film with a periodic arrangement of cut-through slits, an anisotropic metallic metamaterial film, mimics a dielectric slab and supports guided electromagnetic waves in the direction perpendicular to the slits. Here, we introduce metallic metasurface superlattices that include multiple slits in a period, and demonstrate that the superlattices support the Fano resonances and bound states in the continuum. The number of Fano resonances and bound states depend on the number of slits in a period of superlattices. The metallic metasurface superlattices provide new mechanisms to manipulate electromagnetic waves, ranging from microwave to far-infrared wavelengths, where a conventional metal can be considered as a perfect electric conductor.