Nanoscale Radiative Transfer and Properties with Metamaterials and Graphene

Tunneling of evanescent modes enables the radiative heat flux to be several orders of magnitude higher than that between far-field blackbodies, especially when surface plasmon polaritons are excited. Nanoscale thermal radiation has received much attention lately due to its potential applications in energy harvesting, nanomanufacturing, thermal imaging, local heat removal, and vacuum thermal rectifiers. Different micro/nanostructured materials have been considered for enhancing the radiative heat flux, such as doped silicon nanowires and nanoholes, carbon nanotubes, multilayers, gratings, and graphene sheets. Due to its unique characteristics, graphene can support surface plasmon with low loss and excellent tunability ranging from near-infrared to terahertz frequencies. Our recent calculations show that nanowires and graphene covered gratings and nanowires can significantly enhance near-field radiative transfer due to coupled surface plasmon polaritons, hyperbolic metamaterials, as well as hybridized graphene plasmon with other modes. Furthermore, graphene plasmon can be coupled with gratings to enhance infrared absorption or transmission in the far field.