Acoustic Graphene Plasmon Nanoresonators for Field Enhanced Infrared Molecular Spectroscopy

TL;DR

This paper introduces a graphene plasmonic nanoresonator with acoustic graphene plasmons that significantly enhances electromagnetic fields for highly sensitive infrared molecular spectroscopy, enabling detection of ultra-small molecular samples.

Contribution

The study proposes a novel nanoresonator design supporting acoustic graphene plasmons, offering improved field confinement and sensitivity over conventional graphene plasmons.

Findings

Supports ultra-confined electromagnetic fields

Enhances molecular vibrational fingerprint detection

Increases spontaneous emission rate for sensing applications

Abstract

Field-enhanced infrared molecular spectroscopy has been widely applied in chemical analysis, environment monitoring, and food and drug safety. The sensitivity of molecular spectroscopy critically depends on the electromagnetic field confinement and enhancement in the sensing elements. Here we propose a concept for sensing, consisting of a graphene plasmonic nanoresonator separated from a metallic film by a nanometric spacer. Such a resonator can support acoustic graphene plasmons, AGPs; that provide ultra-confined electromagnetic fields and strong field enhancement. Compared to conventional plasmons in graphene, AGPs exhibit a much higher spontaneous emission rate, higher sensitivity to the dielectric permittivity inside the AGP nano resonator, and remarkable capability to enhance molecular vibrational fingerprints, of nanoscale analyte samples. Our work opens novel avenues for sensing of ultra-small volume of molecules, as well as for studying enhanced light-matter interaction, e.g. strong coupling applications.