Multi-Unit Terahertz Frequency Selective Fingerprint Sensor: Wideband Identification of Trace Substances

Terahertz (THz) spectroscopy is a widely utilized technique in biomedical and security detection, as it enables the direct characterization of chemically specific molecular structures within this spectral range. Nevertheless, the current detection methods present considerable obstacles in the analysis of trace samples and the wideband detection of analytes. Fano resonance metasurfaces are employed to enhance light-matter interactions, and a multi-unit combination approach is proposed for the generation of broadband signals (0.3~2.0 THz) for molecular fingerprinting. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\alpha$</tex> -Lactose at 1 mmol/L (0.3423 mg/mL) was successfully identified with this band by utilizing three frequency points (0.53, 1.20, and 1.38 THz). This study provides a method for the miniaturization of THz spectroscopy equipment and field deployment applications.