A coupled harmonic oscillator model to describe the near-field radiative heat transfer between nanoparticles and planar surfaces

TL;DR

This paper introduces a coupled harmonic oscillator model to describe near-field radiative heat transfer between nanoparticles and surfaces, providing an alternative to traditional fluctuational electrodynamics methods.

Contribution

The paper presents a novel coupled harmonic oscillator approach to model surface mode interactions in near-field heat transfer, offering a simplified alternative to existing theories.

Findings

Model accurately predicts heat transfer between nanoparticles and surfaces.

Results agree with fluctuational electrodynamics predictions.

Simplifies analysis of near-field radiative heat transfer.

Abstract

When two objects made of a material which supports surface modes are brought in close proximity to each other such that the vacuum gap between them is less than the thermal wavelength of radiation, then the coupling between the surface modes provides an important channel for the heat transfer to occur which is different from that mediated by long range propagating electromagnetic waves. Indeed, the heat transfer then exceeds Planck's blackbody limit by several orders of magnitude, and consequently has been used for several energy applications such as near-field thermophotovoltaic systems. This near-field radiative heat exchange has been traditionally and successfully described using fluctuational electrodynamics principles. Here, we describe an alternate coupled harmonic oscillator model approach which can be used to model the coupling between surface modes and hence the resultant near-field heat transfer. We apply this theory to estimate the near-field heat transfer for the configurations of two metallic nanoparticles and two planar metal surfaces and compare the result with predictions from fluctuational electrodynamics theory.