Ultra‐wideband enhancement on mid‐infrared fingerprint sensing for 2D materials and analytes of monolayers by a metagrating

Mid‐infrared absorption spectroscopy is a powerful tool to identify analytes by detecting their material fingerprint in a label‐free way, but it faces barriers on trace‐amount analysis due to the difficulties in enhancing the broadband spectral signals. Here, we propose a sensing scheme based on the angular scanning of polarized light on a dielectric metagrating, and demonstrate it by numerical simulation. This approach not only indicates a series of significant signal enhancement factors over 30 times in an ultra‐wide mid‐infrared band, but also enables the explicit identification for various analytes, including 2D materials and trace‐amount thin film samples. Our method would facilitate mid‐infrared sensing for 2D materials and trace‐amount analysis, and enable many new applications on non‐destructive molecular identification.