Manipulation of Thermal Emission by Use of Micro and Nanoscale Structures

Abstract

In high temperature and vacuum applications, for which heat transfer is predominantly by radiation, the material’s surface texture is of substantial importance. Several micro and nanostructures designs have been proposed to enhance a material’s emissivity and its radiative coherence. Control of thermal emission is of crucial concern in the design of infrared sources, in electronic chip coolants, in high-efficiency photovoltaic cells, and in solar energy conversion. In this review paper, we present microscale and nanoscale structures supporting surface waves for obtaining polarization manipulation of thermal emission, extraordinary coherent thermal radiation, bandgap in the spectral emission, spin symmetry breaking of coupled thermal antenna array, and a broadband infrared absorption.

Metamaterial Window Glass

“…Radiative material properties are famously sensitive, however, and in some cases, ill-defined, often leading to suboptimal application. Further, the most recent decade of research has revealed additional strong dependencies of radiative properties in the near-field in which bulk properties can be dramatically different based on surface structuring at the micro-and nanoscale [1][2][3][4][5][6][7][8]. This sensitivity is a double-edged sword, creating a difficult challenge for analytical or computational design of a nanostructured surface, yet providing the opportunity to tailor precise, coherent properties to manage radiative energy in intelligent ways.…”

Heat meets light on the nanoscale

“…Thermal sources with geometries that provide matching of the high momentum of these surface modes to the free space radiation may exhibit even longer coherence length than planar near-field emitters made of the same material [180,181]. These coherent far-field direc- [194], ©APS), (e) a periodic photonic crystal lattice with embedded GaAs quantum wells (reproduced with permission from [71], ©AIP), and (f) a graphene sheet embedded into a planar Fabry-Perot cavity (reproduced with permission from [200], ©NPG).…”

“…This value exceeds the coherence length of the blackbody emission and is approaching a coherence length of a CO 2 laser. Other coherent thermal emitters based on periodic one-dimensional gratings and two-dimensional photonic crystals with emission peaks observed in near-to-far-IR frequency range have been demonstrated experimentally by using metals and polar dielectrics [180,181,[184][185][186][187][188][189].…”

“…As the polarization direction of emitted light follows the orientation of nanoscale emitters, thermal emission from nanopatterned surfaces can be tailored by introducing local anisotropy of individual emitters' orientation. As shown in Figure 7d [181,193,194], local anisotropy can be introduced by gradually rotating the direction of nanorod antennas patterned on a planar substrate. It has been shown experimentally by Hasman and colleagues that thermal radiation emitted by such a surface exhibits photon momentum characteristics associated with the emission from a revolving medium.…”

“…It has been shown experimentally by Hasman and colleagues that thermal radiation emitted by such a surface exhibits photon momentum characteristics associated with the emission from a revolving medium. This phenomenon is known as the angular Doppler effect [181,193,194], and is a manifestation of the spin-orbit interaction of emitted light. Spin-orbit interactions are also a basis for other interesting optical effects, such as photon analogs of spin-Hall [195][196][197], Magnus [198], and Coriolis [199] effects, which paves the road to many exciting applications of coherent nanoscale thermal sources in the emerging field of spinoptics.…”