Giant radiation heat transfer through the micron gaps

TL;DR

This paper introduces a novel approach to significantly enhance radiation heat transfer across micron-scale gaps by transforming evanescent waves into propagating ones using metamaterials, surpassing traditional near-field limits.

Contribution

It proposes a new paradigm employing metamaterials to enable strong photon tunneling through micron gaps, extending near-field heat transfer effects to larger distances.

Findings

Demonstrates transformation of evanescent waves into propagating waves within a metamaterial.

Shows potential for increased heat transfer efficiency across micron gaps.

Suggests minimal impact on photovoltaic conversion processes.

Abstract

Near-field heat transfer between two closely spaced radiating media can exceed in orders radiation through the interface of a single black body. This effect is caused by exponentially decaying (evanescent) waves which form the photon tunnel between two transparent boundaries. However, in the mid-infrared range it holds when the gap between two media is as small as few tens of nanometers. We propose a new paradigm of the radiation heat transfer which makes possible the strong photon tunneling for micron thick gaps. For it the air gap between two media should be modified, so that evanescent waves are transformed inside it into propagating ones. This modification is achievable using a metamaterial so that the direct thermal conductance through the metamaterial is practically absent and the photovoltaic conversion of the transferred heat is not altered by the metamaterial.