Electric dipole-free interaction of visible light with silver metadimers

摘要

In subwavelength-sized particles, light-induced multipole moments of ordershigher than the electric dipole are usually negligibly small, which allows forthe light-matter interaction to be accurately treated within the electricdipole approximation. In this work we show that in a specially designedmeta-atom, a disc metadimer, the electric quadrupole and magnetic dipole can bethe only excitable multipoles. This condition is achieved in a narrow buttunable spectral range of visible light both for individual metadimers and fora periodic array of such particles. The electromagnetic fields scattered by themetadimers fundamentally differ from those created by electric dipoles. Ametamaterial composed of such metadimers will therefore exhibit unusual opticalproperties.