Surface-enhanced Raman scattering from silica core particles covered with silver nanoparticles

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 scatterings. 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 in both effective volume in which molecules are affected by enhanced electric field and Raman gain averaged over this volume.