Far field thermal radiation through nanoholes and apertures

Thermal radiation through a nanohole or a nanoaperture is calculated in this paper. Results show that for aperture size ≪ dominant wavelength of thermally excited photons, heat flux deviates significantly from the well-known Planck blackbody expression of σT4, where σ is the Stefan−Boltzmann constant and T is the temperature. The heat flux through a nanohole is proportional to T8 and a4, where a is the radius of the hole. Finally it is shown that for aT < 106, where a is expressed in nm and T is expressed in K, radiative heat flux through the hole is proportional to T8 and for aT > 106 radiative heat flux is equal to the Planck blackbody heat flux; i.e., it is proportional to T4.