Dark modes excitation and symmetry related properties of metasurfaces

The objective of the present work is to introduce a new concept of direct dark mode excitation mechanism in a metasurface structure. The dark mode excitation is entirely determined by structures' symmetry and does not depend on hybridization mechanism related to near-field coupling between elements. In our examples we consider single element based metasurface composed of two V nano-antennas having an anti-symmetric arrangement. Both experimental and modeling results show an efficient excitation of dark mode in such structures. The considered approach opens promising perspectives for new type of nanostructure designs and greatly relaxes fabrication constraints for the optical domain where such kind of resonances presenting sharp spectral features with steep intensity variation are highly desirable for sensing applications.