Suppression of long-range collective effects in meta-surfaces formed by plasmonic antenna pairs

Abstract

The collective effects in a periodic array of plasmonic double-antenna meta-molecules are studied. We experimentally observe that the collective behavior in this structure substantially differs from the one observed in their single-antenna counterparts. This behavior is explained using an analytical dipole model. We find that in the double-antenna case the effective dipole-dipole interaction is significantly modified and the transverse long-range interaction is suppressed, giving rise to the disappearance of Wood's anomalies. Numerical calculations also show that such suppression of long-range interaction results in an anomalous spatial dispersion of the electric-dipolar mode, making it insensitive to the angle of incidence. In contrast, the quadrupolar mode of the antenna pair experiences strong spatial dispersion. These results show that collective effects in plasmonic metamaterials are very sensitive to the design and topology of meta-molecules. Our findings envision the possibility of suppressing the spatial dispersion effects to weaken the dependence of the metamaterials' response on the incidence angle.

Fano-resonant metamaterials and their applications

“…Depending on the exact structure of constituent meta-molecules, long-range interaction may be either suppressed (incoherent meta-surfaces), or enhanced (coherent meta-surfaces) [64,90]. Coherent effects in Fano-resonant meta-surfaces are reviewed below.…”

Gyromagnetically Induced Transparency of Metasurfaces

“…The spatial symmetries of electric charge distribution on the metamaterial's surface determine whether the EM resonance is "bright" (radiatively coupled to) or "dark" (radiatively de-coupled from) the EM continuum. As we demonstrate in this letter, other symmetries and their breaking can also be crucial to determine the properties of EM resonances and enable their mutual coupling, which in turn can give rise to EM Fano interferences.We consider a meta-surface formed by a two-dimensional array of double-antenna metamolecules [ 34] [ Fig.1(a)]. Such meta-molecules support two low-frequency resonances formed by hybridization of the dipolar modes of the individual antennas that have distinct symmetric and anti-symmetric charge/current distributions responsible for their strongly disparate radiative coupling.…”

“…We consider a meta-surface formed by a two-dimensional array of double-antenna metamolecules [ 34] [ Fig.1(a)]. Such meta-molecules support two low-frequency resonances formed by hybridization of the dipolar modes of the individual antennas that have distinct symmetric and anti-symmetric charge/current distributions responsible for their strongly disparate radiative coupling.…”

Optical properties of Fano-resonant metallic metasurfaces on a substrate

“…Figure 4(a) shows that for the case of a symmetric cladding we observe the effect of "dragging" of the mode by the Wood's anomaly, 32,33 which results in its strong spatial dispersion. This strongly dispersive character of the mode is a manifestation of its collective origin.…”

“…5,[29][30][31][32] Indeed, a few of the above-mentioned phenomena, including collective effects and Fano resonances, can be adequately described by this model. 33 However, there are situations when the dipole model is inadequate. For instance, as soon as the scatterers or the metamolecules forming the array become comparable in size to the wavelength of light, the dipole-dipole interaction mechanism breaks down because interactions through higher multipoles come into play.…”