Radiative heat flux predictions in hyperbolic metamaterials

•We determine the exact heat flux expression in hyperbolic multilayer materials.•We compare results of exact S-matrix calculations with effective medium results.•We find a large attenuation length of the heat flux in hyperbolic metamaterials.

The transport of heat mediated by thermal photons in hyperbolic multilayer metamaterials is studied using the fluctuational electrodynamics theory. We discuss the dependence of the attenuation length and the heat flux on the design parameters of the multilayer structure. We demonstrate that in comparison to bulk materials the flux inside layered hyperbolic materials can be transported at much longer distances, making these media very promising for thermal management and for near-field energy harvesting.