Fig. S3.
Effective material properties of plasmonic superlattices. Real (A) and imaginary (B) effective dielectric functions εeff for superlattices with varying volume fraction. Dashed lines represent εeff including surface scattering that was determined using the size of the constituent spheres. For EMT, only the Au volume fraction is used as input; sphere sizes are provided only as a reference to the superlattice studied (Table 1, main text). εeff is easily related to the refractive index via where μ = 1. Here, Im{εeff} represents absorption by the material, which dominates LSPR extinction in the small-particle quasi-static limit (main text). Re{εeff} signifies the concentration of electric flux; in thin films it contributes minimally to extinction, although in larger systems on the order of the wavelength of light it controls the photonic properties of the crystal.