Hybrid modes in a single thermally excited asymmetric dimer antenna

TL;DR

This paper investigates hybrid electromagnetic modes in a thermally excited asymmetric dimer antenna using infrared spatial modulation spectroscopy, revealing how these modes influence the antenna's far-field response.

Contribution

It introduces a novel experimental approach to study thermally excited hybrid modes in asymmetric antenna dimers and analyzes their impact on electromagnetic response.

Findings

Observation of hybrid bonding and antibonding modes via IR-SMS

Analysis of mode effects on far-field response

Validation of plasmon hybridization model for asymmetric dimers

Abstract

The study of hybrid modes in a single dimer of neighboring antennas is an essential step to optimize the far-field electromagnetic (EM) response of large-scale metasurfaces or any complex antenna structure made up of subwavelength building blocks. Here we present far-field infrared spatial modulation spectroscopy (IR-SMS) measurements of a single thermally excited asymmetric dimer of square metal-insulator-metal (MIM) antennas separated by a nanometric gap. Through thermal fluctuations, all the EM modes of the antennas are excited and hybrid bonding and antibonding modes can be observed simultaneously. We study the latter within a plasmon hybridization model, and analyse their effect on the far-field response.