Long-Range Coupling of Toroidal Moments for the Visible
Surong Guo
Nahid Talebi
Peter A. van Aken
10.1021/acsphotonics.7b01313.s001
https://acs.figshare.com/articles/journal_contribution/Long-Range_Coupling_of_Toroidal_Moments_for_the_Visible/5870730
Dynamic toroidal
multipoles are the third independent family of
elementary electromagnetic sources in addition to electric and magnetic
multipoles. Whereas the dipole–dipole coupling in electric
and magnetic multipole families has been well studied, such fundamental
coupling effects in the toroidal multipole family have not yet been
experimentally investigated. Here we propose a plasmonic decamer nanocavity
structure to realize transverse coupling between magnetic toroidal
dipoles. The coupling effect was investigated both experimentally
and theoretically, by means of electron energy-loss spectroscopy and
energy-filtered transmission electron microscopy, together with finite-difference
time-domain calculations. We observe that the coupling causes a reorientation
of the magnetic moment loops surrounding the initial toroidal moments.
This coupling results in three eigenstates of this toroidal system.
The underlying coupling mechanism is qualitatively demonstrated. Our
investigations pave the way toward a better understanding of coupling
phenomena of toroidal moments and will bias applications in the long-range
ordering of moments in metamaterials, e.g., for transfer of electromagnetic
energy using toroidal moments (by analogy with chain metallic waveguides).
2018-01-27 00:00:00
Visible Dynamic toroidal multipoles
electron energy-loss spectroscopy
energy-filtered transmission electron microscopy
plasmonic decamer nanocavity structure
toroidal multipole family
toroidal moments
finite-difference time-domain calculations