Prediction and Optimization of Surface-Enhanced Raman Scattering Geometries using COMSOL Multiphysics

Raman spectroscopy is a commonly used tool in bio-diagnostics and sensor technology. Surface-enhanced Raman scattering provides high signal enhancements especially at nanostructured metallic surfaces. In this paper the electromagnetic Raman enhancement from different metallic nanostructures – including gold coated gratings, spherical and hemispherical particles – is calculated by using the finiteelement method. The characteristic dimensions of the nanostructures are varied and the results are discussed and compared to each other. It is shown that hemispherical particles on a substrate promise the largest enhancement factors of up to seven orders of magnitude. These results are consistent with Raman spectroscopic measurements on surfaces covered with spherical gold particles.