Fano resonance resulting from a tunable interaction between molecular vibrational modes and a double-continuum of a plasmonic metamolecule

TL;DR

This paper demonstrates tunable Fano resonances in a plasmonic metamolecule array caused by interaction with molecular vibrational modes, combining experimental, electromagnetic, and quantum models for comprehensive understanding.

Contribution

It introduces a quantum mechanical model for plasmon-molecule coupling and experimentally verifies tunable Fano resonances via polarization control.

Findings

Fano resonance observed from plasmon-molecule interaction

Resonance tunable in situ by light polarization

Quantum model agrees with experimental data

Abstract

Coupling between tuneable broadband modes of an array of plasmonic metamolecules and a vibrational mode of carbonyl bond of poly(methyl methacrylate) is shown experimentally to produce a Fano resonance, which can be tuned in situ by varying the polarization of incident light. The interaction between the plasmon modes and the molecular resonance is investigated using both rigorous electromagnetic calculations and a quantum mechanical model describing the quantum interference between a discrete state and two continua. The predictions of the quantum mechanical model are in good agreement with the experimental data and provide an intuitive interpretation, at the quantum level, of the plasmon-molecule coupling.