Decomposing the scattered field of two-dimensional metaatoms into multipole contributions

Institute of Condensed Matter Theory and Solid State Optics,Friedrich-Schiller-Universitat Jena, Max Wien Platz 1, 07743, Jena, Germany(Dated: February 8, 2010)We introduce a technique to decompose the scattered near eld of two-dimensional arbitrarymetaatoms into its multipole contributions. To this end we expand the scattered eld upon planewave illumination into cylindrical harmonics as known from Mie’s theory. By relating these cylin-drical harmonics to the eld radiated by Cartesian multipoles, the contribution of the lowest orderelectric and magnetic multipoles can be identi ed. Revealing these multipoles is essential for thedesign of metamaterials because they largely determine the character of light propagation. In par-ticular, having this information at hand it is straightforward to distinguish between e ects thatresult either from the arrangement of the metaatoms or from their particular design.