Optical scattering resonances of single plasmonic nanoantennas

TL;DR

This study explores the optical scattering resonances of individual plasmonic nanoantennas, revealing how geometry influences spectral shifts and damping, with implications for nano-optics applications.

Contribution

It provides experimental and theoretical analysis of how arm length and gap size affect plasmonic resonances in single nanoantennas, highlighting radiative damping effects.

Findings

Spectral shifts depend on antenna geometry and hybridization.

Resonances are broader due to enhanced radiative damping.

Model calculations match experimental scattering spectra.

Abstract

We investigate the far-field optical resonances of individual dimer nanoantennas using confocal scattering spectroscopy. Experiments on a single-antenna array with varying arm lengths and interparticle gap sizes show large spectral shifts of the plasmon modes due to a combination of geometrical resonances and plasmon hybridization. All resonances are considerably broadened compared to those of small nanorods in the quasistatic limit, which we attribute to a greatly enhanced radiative damping of the antenna modes. The scattering spectra are compared with rigorous model calculations that demonstrate both the near-field and far-field characteristics of a half-wave antenna.