Radiative-field quantum-coupling between closely-spaced surfaces

TL;DR

This paper presents a quantum-mechanical model of energy transfer between closely spaced surfaces, highlighting the role of photon exchange and resonance in enhancing near-field radiative transfer, with practical implications for nanoscale thermal management.

Contribution

It introduces a quantum formulation for surface energy transfer that accounts for dipole interactions and resonance effects, providing new insights into near-field radiative coupling.

Findings

Radiative transfer is greatly enhanced at resonance conditions.

Transfer depends on the fourth power of wavelength-to-gap ratio.

Near-field and resonance coupling can significantly improve energy transfer.

Abstract

A quantum-mechanical formulation of energy transfer between closely-spaced surfaces is given. Coupling between the two surfaces arises from the atomic dipole-dipole interaction involving transverse-photon exchange. The exchange of photons at resonance greatly enhances the radiation transfer. The spacing (distance) dependence is derived for the quantum well - quantum well situation. The interaction between two planar quantum wells, separated by a gap is found to be proportional to the 4th power of the wavelength-to-gapwidth ratio and to the radiation tunneling factor for the evanescent waves. Expressions for the net power transfer, in the near-field regime, from hot to cold surface for this case is given and evaluated for representative materials. Computational modeling of selected, but realizable, emitter and detector structures and materials shows the benefits of both near-field and resonance coupling (e.g., with 0.1 micron gaps).