Résumé
Planar structures cannot emit more heat by radiation than predicted by Stefan- Boltzmann’s law. However, when two reservoirs are connected by an intermediate slab which is placed in their near-field one can in principle observe a super-Planckian heat flux at separation distances larger than the thermal wavelength, if the evanescent contributions can be perfectly guided through the intermediate slab. In this case study we discuss in particular how the thermal near-field of the surface modes of two SiC reservoirs can be guided through an ideal dielectric, a perfect lens and a hyperbolic waveguide. A detailed study of the parameters needed in order to have a long-range guiding of thermal radiation shows which properties are ideally needed in order to observe a super-Planckian heat flux. In particular hyperbolic materials which are known for their large penetration depth of radiative heat fluxes are promising materials. This result opens the way to long distance transport of near-field thermal energy.