Enhancement and Tunability of Near-Field Radiative Heat Transfer Mediated by Surface Plasmon Polaritons in Thin Plasmonic Films

Svetlana Boriskina,Jonathan Tong,Jiawei Zhou,Gang Chen,Yi Huang,Vazrik Chiloyan

doi:10.3390/photonics2020659

Svetlana Boriskina, Jonathan Tong + Show 4 more

Open Access

https://doi.org/10.3390/photonics2020659

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Journal: Photonics	Publication Date: Jun 18, 2015
Citations: 109	License type: CC BY 4.0

Affiliation: Massachusetts Institute of Technology

Abstract

The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength of thermal radiation. Using a rigorous fluctuational electrodynamics approach, we predict that ultra-thin films of plasmonic materials can be used to dramatically enhance near-field heat transfer. The total spectrally integrated film-to-film heat transfer is over an order of magnitude larger than between the same materials in bulk form and also exceeds the levels achievable with polar dielectrics such as SiC. We attribute this enhancement to the significant spectral broadening of radiative heat transfer due to coupling between surface plasmon polaritons (SPPs) on both sides of each thin film. We show that the radiative heat flux spectrum can be further shaped by the choice of the substrate onto which the thin film is deposited. In particular, substrates supporting surface phonon polaritons (SPhP) strongly modify the heat flux spectrum owing to the interactions between SPPs on thin films and SPhPs of the substrate. The use of thin film phase change materials on polar dielectric substrates allows for dynamic switching of the heat flux spectrum between SPP-mediated and SPhP-mediated peaks.

Highlights

Radiative heat transfer between surfaces separated by distances comparable to or shorter than the wavelength of thermal radiation is well-known to deviate from the classical Planck’s law of the blackbody (BB) radiation [1,2,3,4,5,6,7]
Surface waves propagating along the material–vacuum interfaces [4,5,6,8,9,10] can dramatically increase the number of available channels within a certain wavelength range, playing a major role in enhancing and spectrally-tailoring near-field radiative heat transfer across sub-micron gaps
Near-field heat transfer mediated by surface phonon polariton (SPhP) waves supported in silicon carbide (SiC) and silica (SiO2) have been extensively studied and shown to increase radiative heat transfer by orders of magnitude beyond the predictions from Planck’s law [3,4,9,11,12,13,14]

Summary

Introduction

Radiative heat transfer between surfaces separated by distances comparable to or shorter than the wavelength of thermal radiation is well-known to deviate from the classical Planck’s law of the blackbody (BB) radiation [1,2,3,4,5,6,7]. A tradeoff between the peak(s) amplitude and width dictates the optimum level of material dissipative losses This is illustrated, which shows the near-field radiative heat flux spectra mediated by SPP waves for different plasmonic materials with a comparison to the well-studied case of near-field heat transfer via coupled SPhP waves on SiC-air interfaces. We chose AZO and VO2 to illustrate two characteristic cases of the SPP-mediated heat transfer: (i) with the SPP peak overlapping the thermal emission spectrum (AZO), and (ii) with the SPP peak blue-shifted from the thermal emission spectrum (VO2) The width of the spectral peaks for SPP-mediated heat flux in the frequency domain compensates for the suppression of the high-momentum states

Optimization of the Plasmonic Films Materials and Morphology

Findings

Beyond the Single Film: the Effect of Substrate and Multi-Layer Coupling