Infrared thermal emission from a two-dimensional array of plasmonic spheres

We explore in numerical simulation the degree to which the thermal emission in the mid-infrared (IR) range can be controlled using a lattice of plasmonic spheres. While it has been shown that a great deal of spectral control can be achieved using a single sphere, obviously no directional control exists. We propose gaining this additional directional control over the thermal emission by designing a 2D lattice of resonant spheres. In this paper, we demonstrate that directional control as well as additionally spectral control over the thermal emission is achieved with this method. We do this by simulating a 2D layer of spheres composed of SiO2 cores and a SiC shells with a polaritonic resonance in the mid-IR. We then analyze how changing the lattice geometry affects the thermal emission characteristics of the ensemble of spheres. We show that for closely spaced spheres, modest directional control is possible with the additional benefit of some spectral control. When the spheres are spaced farther apart, Bragg scattering allows for more directional control, however, the spectrum of the emission is mostly governed by the properties of a single sphere.