Bifacial Metasurface with Quadrupole Optical Response

Abstract

As metamaterials research continues to evolve, we may consider effects and systems that go beyond the electric-dipole approximation. The authors fabricate an optical metasurface in which nanoscale artificial metamolecules exhibit a dominant electric-current quadrupolar response at visible wavelengths, and the optical reflection and absorption change considerably when the illumination direction is reversed. This bifacial metasurface could be applied in interferometric devices and coatings, solar cells, or directional optical elements such as light sources and detectors.