Enhanced Raman Scattering by Two-Dimensional Array of Polarizable Spheres

Two-dimensional array of dielectric spheres gives rise to prominent peaks in the reflectivity spectrum of light, corresponding to the excitation of the localized modes. We demonstrate that these localized modes provide a new possibility of enhanced Raman scattering from a molecule adsorbed on arrayed dielectric spheres. It is found that the enhancement factor of order 10 4 is easily achieved, when the incidence and scattering angles of light are appropriate. By calculating the dispersion relation of the localized modes, we show that the excitation of them is clearly the origin of such a large enhancement. We also examine the enhanced Raman scattering for arrayed metallic spheres.