8 Controlling Thermal Radiation with Surface Waves
315
(a)
(c)
(b)
Fig. 8.21 a Transmission coefficient T p (ω, κ) between two SIC periodic arrays separated by a
distance d = 100 nm. b Real part of the parallel and orthogonal components of dielectric tensor. c
Normalized heat transfer coefficient for two hyperbolic materials with f = 0.1, 0.2, 0.3
of materials for heat transfer at the nanoscale. Their efficiency is based on a broad
range of frequencies where the transmission factor can be large. In practice, there
is a cutoff in κ and therefore for d. It is due to the validity of the homogenization
approximation. The order of magnitude of the cutoff is given by 1/a where a is the
average nanorod spacing.
8.2.5 Applications
8.2.5.1 Thermal Management with Anisotropic Media
A proper understanding of near-field heat transfer naturally gives rise to new ideas
on how to control the heat flux between closely separated structures, i.e., on thermal
management at the micro/nanoscale. Such a control can be achieved, for instance,
by thermal rectifiers [7, 89], thermal transistors [88] and thermal modulators [16,