Towards a black body for near-field thermal radiation
  We study the near-field heat exchange between hyperbolic materials and demonstrate that these media are able to support broadband frustrated modes which transport heat by photon tunnelling with a high efficiency close to the theoretical limit. We predict that hyperbolic materials can be designed to be perfect thermal emitters at nanoscale and derive the near-field analog of the blackbody limit. 
S.-A. Biehs, M. Tschikin, and P. Ben-Abdallah
cond-mat.mes-hall quant-ph