An incandescent metasurface for quasimonochromatic polarized mid-wave infrared emission modulated beyond 10 MHz

Abstract

Incandescent sources such as hot membranes and globars are widely used for mid-infrared spectroscopic applications. The emission properties of these sources can be tailored by means of resonant metasurfaces: control of the spectrum, polarization, and directivity have been reported. For detection or communication applications, fast temperature modulation is desirable but is still a challenge due to thermal inertia. Reducing thermal inertia can be achieved using nanoscale structures at the expense of a low absorption and emission cross-section. Here, we introduce a metasurface that combines nanoscale heaters to ensure fast thermal response and nanophotonic resonances to provide large monochromatic and polarized emissivity. The metasurface is based on platinum and silicon nitride and can sustain high temperatures. We report a peak emissivity of 0.8 and an operation up to 20 MHz, six orders of magnitude faster than commercially available hot membranes.

Whole LWIR Directional Thermal Emission Based on ENZ Thin Films

“…[40] Third, the directional emission angle and working wavelength ranges can be tailored by ENZ material choices, such as indium-tin-oxide (ITO) and cadmium oxide (CdO) at NIR wavelength. [41][42][43][44][45] Last, the whole LWIR directional thermal emitter shows good directionality and polarization property; therefore, we believe that it can be used in more applications, such as thermal emission sources, [46][47][48] energy management, [49][50][51] infrared camouflage, [52][53][54] and radiative cooling. [55][56][57][58]…”

Perspective: Phonon polaritons for infrared optoelectronics

“…This approach has even been shown to work down to the single antenna level [77]. Recently dynamic manipulation of thermal emission has been demonstrated by electrical modulation [78,79] or the use of photochromic materials [80]. Thermal emitters have excellent prospects in areas such as passive cooling [81] but are ultimately limited by the spontaneous emission process through which they are powered.…”

Electrically Driven Hyperbolic Nanophotonic Resonators as High Speed, Spectrally Selective Thermal Radiators

“…Spectrally tailored thermal emitters have been made possible by globally heating metamaterials, − which are subwavelength-scale structured media that can support narrowly peaked emissivity spectra corresponding to engineered absorptive resonances, as dictated by Kirchhoff’s law. Fast modulation from thermal emitters has been achieved by use of innovative materials that feature novel tuning mechanisms − or exceptionally small volumes, − which enable fast variations in temperature − though with limited spectral control. Hybrid device schemes that couple thermal emitters to optical cavities can combine fast modulation with spectral selectivity, ,,− but their implementation in the form of multiple fast emitters operating at unique wavelengths remains an integration challenge.…”

“…Fast modulation from thermal emitters has been achieved by use of innovative materials that feature novel tuning mechanisms − or exceptionally small volumes, − which enable fast variations in temperature − though with limited spectral control. Hybrid device schemes that couple thermal emitters to optical cavities can combine fast modulation with spectral selectivity, ,,− but their implementation in the form of multiple fast emitters operating at unique wavelengths remains an integration challenge.…”

“…A theoretical model of the emission spectra agrees well with our experimental findings and further reinforces that the hyperbolic metamaterial resonances control the emission spectra. We use the local Kirchhoff law for an anisothermal emitter because the CNT resonators are locally heated, , and we consider a simplistic model that assumes that the emission originates from CNT resonators at one temperature, T CNT , and from the heated oxide at an arbitrarily assumed temperature T ox . We model the integrated absorption of each component using a two-dimensional finite element method electromagnetic simulation (see the Supporting Information) with previously measured effective dielectric functions for the CNT metamaterial. , Our model gives emission spectra that agree well with the experimentally measured spectra (Figure b).…”