Tunable Wide Angle Infrared Absorption and Selective Thermal Emission in Graphene Decorated with Metallic Nanoparticles

We showed in past work that graphene decorated with metallic nanoparticles, such as Ag nanocubes or nanospheres, enables spectrally selective thermal emission in the atmospherically opaque regime between λ = 5 μm and λ = 8 μm and the atmospherically transparent regime between λ = 8 μm and λ = 12 μm, by means of acoustic graphene plasmons (AGPs) localized between graphene and the Ag nanoparticle inside a dielectric material. Here we expand upon these results to calculate wide angle mid-IR absorption and thermal emission by means of finite-element time domain (FETD) calculations. Our FETD calculations show that our proposed structure retains significant absorption in the mid-IR regime at wide angles of incident while retaining the thermal selectivity by means of a gate voltage. These angular-dependent results also show electrostatically tunable radiative-heating capabilities. Our theoretical results can thus be used to develop graphene-based wide-angle mid-IR sensors as well as tunable smart fabrics for cold environments.