Near- and Far-Field Optical Properties of Dipole-Multipole Plasmonic Coupled Building Blocks

Abstract

The plasmonic hybridization in the complex nanostructure innovates multiple fields, such as chemistry, physics, materials science, and biology. In this article, we systematically studied the near- and far-field optical properties of building blocks of coupled dipoles or coupled dipoles and multipoles or a multipole in a coupled plasmonic system through numerical simulations. To be specific, the far-field spectrum, near-field phase changes, and angular radiation patterns of plasmonic hybridized structures were calculated. Also, the “gap separation effect” on the strength of plasmonic hybridization was discussed via spectral and near-field evaluation. Additionally, we investigated the coupling between building blocks and different shapes of dipoles through the near- and far-field study. To some extent, our studies have theoretically proven that, compared to the plasmonic coupling among dipoles, the coupling between multipoles and dipoles show mostly comparative and even stronger hybridization in terms of both near- and far-field, which led to the expanded broad range of resonance and stronger localized E-field. We believe that our work may contribute to the fundamental understanding of the plasmonic hybridization system and pave the path for new applications and opportunities in vast regimes of plasmonic-photonic and nanoplasmonic.