# Independent engineering of individual plasmon modes in plasmonic dimers with conductive and capacitive coupling

## TL;DR

This study demonstrates independent control of different plasmonic modes in nanoparticle dimers with conductive or capacitive junctions, using spectroscopy and simulations, and introduces a method to reconstruct near-field distributions via Babinet's principle.

## Contribution

It reveals the coexistence of hybridized plasmon modes with distinct sensitivities to junction properties and shows how Babinet's principle can engineer near fields independently of mode energy.

## Key findings

- Strong and weak hybridized modes coexist in nanoparticle dimers.
- Properties of strongly hybridized modes depend on junction type.
- Near-field distributions can be reconstructed using Babinet's principle.

## Abstract

We revisit plasmonic modes in nanoparticle dimers with conductive or insulating junction resulting in conductive or capacitive coupling. In our study which combines electron energy loss spectroscopy, optical spectroscopy, and numerical simulations, we show coexistence of strongly and weakly hybridized modes. While the properties of the former ones strongly depend on the nature of the junction, the properties of the latter ones are nearly unaffected. This opens up a prospect for independent engineering of different plasmonic modes in a single plasmonic antenna. In addition, we show that Babinet's principle allows to engineer the near field of plasmonic modes independent of their energy. Finally, we demonstrate that combined electron energy loss imaging of a plasmonic antenna and its Babinet-complementary counterpart allows to reconstruct the distribution of both electric and magnetic near fields of localised plasmonic resonances supported by the antenna as well as charge and current antinodes of related charge oscillations.