Radiative heat transfer between dielectric bodies

TL;DR

This paper reviews the macroscopic theory of radiative heat transfer between dielectric bodies, especially in the context of recent nanometer-scale measurements, and discusses its validity limits based on fluctuating electrodynamics.

Contribution

It revisits the macroscopic fluctuating electrodynamics theory in light of recent experimental advances at nanometer scales.

Findings

The theory aligns with measurements down to a few nanometers.

Limits of the macroscopic theory are discussed for very small distances.

Highlights the need for potential microscopic models at sub-10-8m scales.

Abstract

The recent development of a scanning thermal microscope (SThM) has led to measurements of radiative heat transfer between a heated sensor and a cooled sample down to the nanometer range. This allows for comparision of the known theoretical description of radiative heat transfer, which is based on fluctuating electrodynamics, with experiment. The theory itself is a macroscopic theory, which can be expected to break down at distances much smaller than 10-8m. Against this background it seems to be reasonable to revisit the known macroscopic theory of fluctuating electrodynamics and of radiative heat transfer.