Near-field radiative heat transfer between arbitrarily shaped objects and a surface

Abstract

A fluctuational electrodynamics-based formalism for calculating near-field radiative heat transfer between objects of arbitrary size and shape and an infinite surface is presented. The surface interactions are treated analytically via Sommerfeld's theory of electric dipole radiation above an infinite plane. The volume integral equation for the electric field is discretized using the thermal discrete dipole approximation (T-DDA). The framework is verified against exact results in the sphere-surface configuration, and is applied to analyze near-field radiative heat transfer between a complex-shaped probe and an infinite plane both made of silica. It is found that when the probe tip size is approximately equal to or smaller than the gap d separating the probe and the surface, coupled localized surface phonon (LSPh)-surface phonon-polariton (SPhP) mediated heat transfer occurs. In this regime, the net spectral heat rate exhibits four resonant modes due to LSPhs along the minor axis of the probe while the net total heat rate in the near field follows a d-0.3 power law. Conversely, when the probe tip size is much larger than the separation gap d, heat transfer is mediated by SPhPs resulting in two resonant modes in the net spectral heat rate corresponding to those of a single emitting silica surface while the net total heat rate approaches a d-2 power law. It is also demonstrated that a complex-shaped probe can be approximated by a

Nanoscale Thermal Transfer – An Invitation to Fluctuation Electrodynamics

“…It is now possible to compute Green functions in quite arbitrary geometries using finite-element techniques called 'discrete-dipole approximation' [47][48][49]. These techniques permit naturally to implement the concept of local, thermal current sources; examples of recent achievements can be found in [7,50,51]. From a correlation function like 〈E k (r)E l (r′)〉 ω , it is easy to compute the electromagnetic energy density (take k = l and r = r′), correlations for the magnetic field (take the curl with respect to both r and r′), and the Poynting vector, for example.…”

Temperature of a nanoparticle above a substrate under radiative heating and cooling

“…The knowledge of the absorption efficiency of the NP is necessary for such kind of problem. Diverse numerical electromagnetic methods are suitable * houssem.kallel@univ-poitiers.fr; houssem.kallel@yahoo.fr † remi.carminati@espci.fr ‡ karl.joulain@univ-poitiers.fr for the computation of the optical response of a single NP in the presence of a substrate such as the Discrete Dipole Approximation with Surface Interaction (DDA-SI) [19][20][21], the Boundary Element Method (BEM) [22], and the generalized Mie theory (T-matrix method or exact multipole expansion method) [23][24][25][26][27]. Approximate methods, with considerably less computational resource requirements, can also be used, for example, the image dipole approach [28] and the effective (or dressed) polarizability approach [16,29].…”

Near-Field Radiative Heat Transfer under Temperature Gradients and Conductive Transfer

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