Large circular dichroism in the emission from an incandescent metasurface

Compact sources in the mid-wave infrared (MWIR) are needed for applications ranging from spectroscopy to freespace communication. Ultrathin incandescent metasurfaces are promising candidates, offering the possibility to tune the emission spectrum, directivity, and modulation speed. However, control over polarization remains a challenge, especially when it comes to the emission of circularly polarized light. Here, we report the emission of polarized MWIR radiation from a 700 nm thick incandescent chiral metasurface. The degree of polarization is above 0.5 with degree of circular polarization of 0.38 at 5 mu m. The metasurface is heated by the Joule effect, and the emission can be modulated beyond 10 MHz. This could enable detection techniques that use polarization as an additional degree of freedom. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This study reports the emission of polarized mid-wave infrared (MWIR) radiation from a 700 nm thick incandescent chiral metasurface. The polarization degree is above 0.5 with a circular polarization degree of 0.38 at 5 μm. The metasurface is heated by the Joule effect and the emission can be modulated beyond 10 MHz. This could enable detection techniques that use polarization as an additional degree of freedom.