Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice

Plasmonic lattice nanostructures are of techno-logical interest because of their capacity to manipulate l i g h t below the diffraction limit . Here, we present a detailed study of dark and bright modes in the visible and near-infrared energy regime of an inverted plasmonic honeycomb lattice by a combination of Au+ focused ion beam lithography with nanometric resolution, optical and electron spectroscopy, and finite-difference time-domain simulations. The lattice consists of slits carved in a gold thin film, exhibiting hotspots and a set of bright and d a r k modes. We proposed that some of the dark modes detected by electron energy-loss spectroscopy are caused by antiferroelectric arrangements of the slit polarizations with two times the size of the hexagonal unit cell. The plasmonic resonances tak e place within the 0.5-2 eV energy range, indicating that they could be suitable for a synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.

Automated summary

In this study, dark and bright modes in an inverted plasmonic honeycomb lattice in the visible and near-infrared energy regime were investigated. The lattice was made of slits carved in a gold thin film and showed hotspots and a set of bright and dark modes. The plasmonic resonances were found to occur within the 0.5-2 eV energy range, suggesting their potential for synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.