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

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 20MHz, six orders of magnitude faster than commercially available hot membranes. Incandescent sources are needed for mid-infrared spectroscopy. Here, the authors present a metasurface of nanoheaters that enables fast thermal modulation beyond 10MHz and emissivity with well controlled emission spectrum and polarization.

Automated summary

In order to achieve fast thermal response, reducing thermal inertia using nanoscale structures is possible, but it may result in low absorption and emission cross-sections.