  The spectral characteristics of near-field thermal emission from nanoparticle
arrays are explained by comparison to the dispersions for propagating modes.
Using the coupled dipole model, we analytically calculate the spectral emission
from single particles, chains, planes, and 3D arrays of SiO2 and SiC. We show
that the differences in their spectra are due to the existence or absence of
propagating surface phonon polariton modes and that the emission is dominated
by these modes when they are present. This work paves the way for understanding
and control of near-field radiation in nanofluids, nanoparticle beds, and
certain metamaterials.
