Exact solutions of the 3D Maxwell equations.
Extra enhancement of SERS via path interference phenomenon. Presence of a QE, in , does not change the localization of the fields on the Raman-active molecule (localization enhancement remains unchanged). The presented enhancement factors, up to 5000, multiply the localization enhancement. The extra (interference) enhancement appears in the spectral position predicted by the analytical model, in Eq. (13), and shifts to longer wavelengths with stronger QE coupling ().