On cavity-and-surface enhanced Raman scattering from metamaterial shells

TL;DR

This paper theoretically demonstrates that core-shell metamaterial particles with epsilon-near-zero shells can combine cavity and surface resonance effects to significantly enhance Raman scattering, improving detection sensitivity.

Contribution

It introduces a novel design of core-shell particles with epsilon-near-zero metamaterial shells that synergistically enhance Raman signals through combined cavity and plasmon resonances.

Findings

Giant electric field enhancement inside the metashell.

Significant increase in effective volume for Raman enhancement.

Potential for improved molecular detection sensitivity.

Abstract

In this paper we theoretically show that the Raman scattering by a core-shell micron or submicron particle with epsilon-near-zero metamaterial shell and silica spherical or cylindrical core can combine useful features of cavity-enhanced and surface-enhanced Raman scattering. The cavity resonance together with the plasmon resonance lead to the giant enhancement of the field inside the metashell which is performed as a layer of silver or gold nanoparticles and is penetrable for molecules to be detected. This approach results in the significant increase of both effective volume in which molecules are affected by enhanced electric field and Raman gain averaged over this volume.