title: Plasmonic Toroidal Dipolar Response under Radially Polarized Excitation.
abstract: Plasmonic toroidal resonance has attracted growing interests because of its low loss electromagnetic properties and potential high sensitive nanophotonic applications. However, the realization in a metamaterial requires three-dimensional complicated structural design so far. In this paper, we design a simple metal-dielectric-metal (MIM) sandwich nanostructure, which exhibits a strong toroidal dipolar resonance under radially polarized excitation. The toroidal dipole moment as the dominant contribution for the scattering is demonstrated by the mirror-image method and further analyzed by Lagrangian hybridization model. The proposed toroidal configuration also shows a highly tolerant for misalignment between the structure center and the incident light focus. Our study proves the way for the toroidal plasmonic application with the cylindrical vector beams.
authors.affiliation: School of Physics, State Key Lab for Mesoscopic Physics, Peking University, Beijing 100871, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Bao
authors.affiliation: School of Physics, State Key Lab for Mesoscopic Physics, Peking University, Beijing 100871, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhu
authors.affiliation: 1] School of Physics, State Key Lab for Mesoscopic Physics, Peking University, Beijing 100871, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Zheyu
authors.initials: Z
authors.lastname: Fang