Loss-Engineered Terahertz Pixelated Metasensors for Enhanced Molecular Vibrational Fingerprint Sensing.

Molecular vibrational fingerprints in the terahertz (THz) regime offer unique opportunities for label-free chemical and biological sensing. Metasensors can amplify these vibrational signals through local near-field enhancement. However, current THz molecular fingerprint metasensors lack a systematic design and optimization methodology, which severely limits their potential. Here, we unveil the crucial role of resonant loss rate in THz molecular fingerprint sensing and present a loss-engineering methodology for optimized molecular vibrational sensing. Based on the proposed methodology, we experimentally demonstrate a 12.6-fold enhancement of the molecular fingerprint signal with three-dimensionally printed pixelated metasensors.  Furthermore, the pixelated metasensors support vibrational strong-coupling, providing a unified platform for enhanced molecular sensing and strong light-matter interaction. Overall, the proposed metasensor could bridge THz molecular vibrational fingerprint sensing to end-use applications in label-free chemical and biomedical detection.