Metasurface-mediated anisotropic radiative heat transfer between nanoparticles

Abstract

Metasurfaces, the two-dimensional (2D) counterpart of metamaterials, have recently attracted a great attention due to their amazing properties such as negative refraction, hyperbolic dispersion, manipulation of the evanescent spectrum. In this work, we propose a theory model for the near field radiative heat transfer (NFRHT) between two nanoparticles in the presence of an anisotropic metasurface. Specifically, we set the metasurface as an array of graphene strips (GS) since it is an ideal platform to implement any metasurface topology, ranging from isotropic to hyperbolic propagation. We show that the NFRHT between two nanoparticles can not only be significantly amplified when they are placed in proximity of the GS, but also be regulated over several orders of magnitude. In this configuration, the anisotropic surface plasmon polaritons (SPPs) supported by the GS are excited and provide a new channel for the near-field energy transport. We analyze how the conductance between two nanoparticles depends on the orientation, the structure parameters and the chemical potential of the GS, on the particle-surface or the particle-surface distances by clearly identifying the characteristics of the anisotropic SPPs such as dispersion relations, propagation length and decay length. Our findings provide a powerful way to regulate the energy transport in the particle systems, meanwhile in turn, open up a way to explore the anisotropic optical properties of the metasurface based on the measured heat transfer properties.

Graphene-based thermal repeater

“…Moreover, the amplification is sorely confined near the interface of the substrate, due to the surface characteristics of graphene surface plasmon polaritons (SPPs).The lack of the connecting between the particles and the substrate, and the nature of SPPs both restrict the relay effect.Graphene exhibits intriguing electronic properties including the presence of strongly confined SPPs which can be excited to transport energy in photonic channels [13,14]. This has been exploited for a more efficient RHT between hybrid periodic structures [15] and between nanoparticles [16]. Recently, by using multilayer structures, the RHT between NPs has been shown to be further increased thanks to a resonant coupling between the substrate surface modes and the NPs resonances [17].…”

Generalized coupled dipole method for thermal far-field radiation

“…Here, we will focus on the dipole model only, which is the theoretical workhorse of many recent works, because of its conceptional and numerical simplicity. For example, using this model it could be shown that the heat transfer between two dipolar objects can be enhanced by the presence of a substrate or more general third objects supporting surface waves like phonon polaritonic media [16][17][18][19][20], graphene [18], Moiré bilayer graphene [21], or hyperbolic media [22,23]. For non-reciprocal media even more interesting many-body effects were demonstrated like persistent heat currents and fluxes [24][25][26][27], giant magnetic resistances [28,29], Hall and anomalous Hall effect [30,31], circular polarized emission and thermal angular momentum and spin [25,32,33] as well as non-reciprocal near-field diodes [34,35] or spin-related directional thermal emission [36].…”

Radiative heat transfer and radiative thermal energy for two-dimensional nanoparticle ensembles

“…The fluctuational electrodynamics theory developed by Rytov et al [1] is the basic theoretical framework to analyze NFRHT. NFRHT between two planar surfaces [2][3][4][5][6][7][8], two isolated nanoparticles [9][10][11], two spheres [12], one dipole and surface [13], two nanoparticles above a substrate [14][15][16][17], and between two nanoparticles separated by a multilayer plate [18] were investigated theoretically recently in such framework. The theory has been set in a general framework, and it is now possible to calculate the NFRHT between two or many bodies of arbitrary shape and dielectric permittivity using a general scattering matrix method [19,20], which was then applied to the many-body system with planar geometry [21].…”