Extraordinary Coherent Thermal Emission From SiC Due to Coupled Resonant Cavities

Abstract

In high temperature and vacuum applications, when heat transfer is predominantly by radiation, the material’s surface texture is of substantial importance. Several micro- and nanostructure designs have been proposed to enhance a material’s emissivity and its radiative coherence, as control of thermal emission is of crucial concern in the design of infrared sources, optical filters, and sensing devices. In this research, an extraordinary coherent thermal emission from an anisotropic microstructure is experimentally and theoretically presented. The enhanced coherency is due to coherent coupling between resonant cavities obtained by surface standing waves, wherein each cavity supports a localized field that is attributed to coupled surface phonon polaritons. We show that it is possible to obtain a polarized quasimonochromatic thermal source from a SiC microstructure with a high quality factor of 600 at the resonant frequency of the cavity and a spatial coherence length of 716 wavelengths, which corresponds to an angular divergence of 1.4mrad. In the experimental results, we measured a quality factor of 200 and a spatial coherence length of 143 wavelengths. We attribute the deviation in the experimental results to imperfections in the fabrication of the high quality factor cavities.

Ca2+‐Doped LaCrO3: A Novel Energy‐Saving Material with High Infrared Emissivity

“…For example, they can be used in thermal furnaces and other high‐temperature processing units for the purposes of energy saving . Thus, the research work to develop coating materials with high IR emissivity for energy‐saving purpose has increased considerably …”

Measurement of Coherent Thermal Emission Due to Magnetic Polaritons in Subwavelength Microstructures

“…In addition, selective thermal emission has been experimentally demonstrated using Fabry-Perot cavity resonators [11,12], but the emission peaks tend to decrease at elevated temperatures due to the increased loss in the metal films. Coherent emission associated with cavity resonant modes was also demonstrated in ID SiC deep gratings at 770K [13]. Although spectral selectivity of thermal emission can be achieved with the above-mentioned microstructures, most of them exhibit sharp emittance peaks and strong directional dependence.…”

Doping-tunable thermal emission from plasmon polaritons in semiconductor epsilon-near-zero thin films

“…Surface gratings or resonant structures have been adopted to alter thermal radiation properties and achieve spectrally selective thermal emission. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] In such patterns, narrowband thermal emission could be obtained at desired frequencies, which are determined by the pattern geometry. In addition, it is possible to get directional thermal emission by adjusting the scattering properties of structured surfaces.…”