Figure 3

Experimental transmittance spectra compared with computed spectra for (a) Au nanoparticle monolayer, (b) Au nanoparticle bilayer, (c) Ag nanoparticle monolayer, (d) Ag nanoparticle bilayer. The near-field enhancement with respect to the incident field is shown in the inset of each plot. The dimensions for the models were taken from the TEM images (Fig. 2). Au nanoparticle diameter and interparticle gap: 10 nm and 2 nm, Ag nanoparticle diameter and interparticle gap: 20 and 2 nm. The direction of incidence of illumination is normal in all cases.