Figure 1.
Schematic diagram of the radiation exchanged via conventional radiative transfer.
Elastic collision of photons with atoms or molecules of materials and phonon-photon coupling contributions between a sphere and a plate maintained at different temperatures, and
, separated by a distance
.
Figure 2.
Sphere-plate near-field heat transfer coefficients between a gold (or glass) sphere and a gold (or glass) substrate versus gap distances.
The data are from Ref [9] for the 50 µm diameter spheres. The dotted lines are comparisons with the theoretical predictions from the proximity theorem. The inset shows a non-divergent regime as the gap vanishes.