Resonant enhancement of Raman scattering in metamaterials with hybrid electromagnetic and plasmonic resonances

TL;DR

This paper demonstrates how a specially designed tri-layer metamaterial can significantly enhance Raman scattering from C-60 molecules by leveraging hybrid electromagnetic and plasmonic resonances at specific wavelengths.

Contribution

It introduces a novel metamaterial structure that combines plasmonic and electromagnetic resonances to boost Raman signals, with detailed numerical analysis of the hybrid resonances.

Findings

Raman scattering is enhanced by an order of magnitude on resonant metamaterials.

Resonant bands at pump and emission wavelengths are crucial for enhancement.

Numerical simulations reveal the hybridization of plasmonic and electromagnetic resonances.

Abstract

A tri-layer metamaterial perfect absorber of light, consisting of (Al/ZnS/Al) films with the top aluminium layer patterned as an array of circular disk nanoantennas, is investigated for resonantly enhancing Raman scattering from C-60 fullerene molecules deposited on the metamaterial. The metamaterial is designed to have resonant bands due to plasmonic and electromagnetic resonances at the Raman pump frequency (725 nm) as well as Stokes emission bands. The Raman scattering from C60 on the metamaterial with resonantly matched bands is measured to be enhanced by an order of magnitude more than from C60 on metamaterials with off-resonant absorption bands peaked at 1090 nm. The Raman pump is significantly enhanced due to the resonance with a propagating surface plasmon band, while the highly impedance matched electromagnetic resonance is expected to couple out the Raman emission efficiently. The nature and hybridization of the plasmonic and electromagnetic resonances to form compound resonances are investigated by numerical simulations.