Magnetic polariton-based thermal emitter for dual-band filterless gas sensing

The miniaturization of infrared gas sensors is largely hindered by expensive and bulky laser sources as well as the use of optical filters. In this work, we propose a dual-band, directional thermal emitter based on compact W-Si-Cu metasurfaces to address this issue. This metasurface emitter is designed to support two nondispersive magnetic polariton modes that exhibit distinct directional thermal emission profiles, thus enabling dual-band detection without the need of optical filters. Specifically, we evaluate the feasibility of such dual-band filterless detection by adapting the metasurface emitter to CO2 sensing. The model of sensing system shows a selective relative sensitivity of CO2 which is 3.2 times higher than that using a blackbody emitter, and a relative sensitivity of temperature of emitter about 1.32%/K.