Material Scaling and Frequency-Selective Enhancement of Near-Field Radiative Heat Transfer for Lossy Metals in Two Dimensions via Inverse Design

Abstract

The super-Planckian features of radiative heat transfer in the near-field are known to depend strongly on both material and geometric design properties. However, the relative importance and interplay of these two facets, and the degree to which they can be used to ultimately control energy flow, remains an open question. Recently derived bounds suggest that enhancements as large as $|\chi {|}^4{\lambda }^2/\left({\left(4\pi \right)}^2\Im {\left[\chi \right]}^2{d}^2\right)$ are possible between extended structures (compared to blackbody); but neither geometries reaching this bound, nor designs revealing the predicted material ($\chi$) scaling, have been previously reported. Here, exploiting inverse techniques, in combination with fast computational approaches enabled by the low-rank properties of elliptic operators for disjoint bodies, we investigate this relation between material and geometry on an enlarged space structures. Crucially, we find that the material proportionality given above does indeed emerge in realistic structures. In reaching this result, we also show that (in two dimensions) lossy metals such as tungsten, typically considered to be poor candidate materials for strongly enhancing heat transfer in the near infrared, can be structured to selectively realize flux rates that come within $50\%$ of those exhibited by an ideal pair of resonant lossless metals for separations as small as $2\%$ of a tunable design wavelength.

6 pages, 2 figures

References in corpus (11)

• Outlook for inverse design in nanophotonics
• Wide-angle perfect absorber/thermal emitter in the THz regime
• Broadband super-Planckian thermal emission from hyperbolic metamaterials
• Radiative heat transfer between nanostructures
• Fluctuating surface-current formulation of radiative heat transfer for arbitrary geometries
• Ideal near-field thermophotovoltaic cells
• Radiative heat transfer between metallic gratings using adaptive spatial resolution
• Thermal excitation of plasmons for near-field thermophotovoltaics
• Near-Field Radiative Heat Transfer Between Metasurfaces: A Full-Wave Study Based on 2D Grooved Metal Plates
• Near-field refrigeration and tunable heat exchange through four-wave mixing
• Fano interference for tailoring near-field radiative heat transfer

Cited by in corpus (11)

• Transforming heat transfer with thermal metamaterials and devices
• Near-field Radiative Heat Transfer in Many-Body Systems
• Maximal nighttime electrical power generation via optimal radiative cooling
• Fundamental limits to radiative heat transfer: theory
• $\mathbb{T}$-operator bounds on angle-integrated absorption and thermal radiation for arbitrary objects
• Fundamental limits to attractive and repulsive Casimir--Polder forces
• Hierarchical Mean-Field $\mathbb{T}$ Operator Bounds on Electromagnetic Scattering: Upper Bounds on Near-Field Radiative Purcell Enhancement
• Mechanical relations between conductive and radiative heat transfer
• Near-field thermal emission from metasurfaces constructed of SiC ellipsoidal particles
• High Resolution Measurement of Near-Field Radiative Heat Transfer enabled by Nanomechanical Resonators
• $\mathbb{T}$-Operator Limits on Optical Communication: Metaoptics, Computation, and Input-Output Transformations