Strong coupling in a Au plasmonic antenna-SiO$_{2}$ layer system: a hybrid mode analysis

TL;DR

This paper investigates the strong coupling effects in a system of gold antennas on a SiO₂ layer, analyzing hybrid modes and their resonant properties through a classical coupled oscillator model in the IR spectrum.

Contribution

It provides a detailed analysis of hybrid modes in a plasmonic-phonon system using a classical model, revealing mode contributions and coupling strengths.

Findings

Identification of four phonon polariton modes coupled to plasmonic modes

Quantification of resonant energies and damping rates

Determination of coupling strengths and mode contributions

Abstract

A detailed analysis of the optical response of a system accommodating several coupled modes is needed for the complete understanding of the strong coupling effect. In this paper, we report on the analysis of scattering cross section spectra of Au antennas on a SiO$_{2}$ layer on a Si substrate in the IR region. A classical model of coupled oscillators is used for determining the resonant energies, damping rates and coupling strengths of four phonon polariton modes in the SiO$_{2}$ layer coupled to a localized surface plasmon mode in a Au antenna. The calculated Hopfield mixing coefficients then show the contribution of the individual uncoupled modes to the hybrid modes of the coupled system.