Dark mode engineering in metasurfaces by symmetry matching approach

We revisit the engineering of metasurfaces to obtain sharp features in their spectral response. We show that in contrast to conventional approach exploiting indirect mode hybridization mechanism based on strong near-field coupling, a more flexible and efficient engineering of the spectral response can be achieved using a symmetry matching approach for the excitation of dark modes. This distinctly different mechanism takes advantage of the geometry symmetry of the structure with regard to the incident external electromagnetic field for a direct far-field coupling.