Local field enhancement effects for dielectric coatings on silver nanorod arrays

Abstract

A slanted silver nanorod array (NRA) deposited with glancing angle of deposition around 89°. By controlling the deposition angle, SiO2 and Ta2O5 grow on sliver rods in different morphologies. The multilayer designed as high reflective multilayer by arranging SiO2 and Ta2O5 alternatively on a cylindrical silver rod with diameter of 80 nm and a length of 200 nm would enhance the local field intensity and scattering when the rod is illuminated by s-polarized and ppolarized light waves. In this work, the reflective multilayer is designed at wavelengths of 450nm and 750nm that are associated with transverse plasmonic mode and longitudinal plasmonic mode, respectively. It is demonstrated experimentally that the intensity of light scattering from the capped NRA is enhanced due to the local field confinement around silver rod.