Pixelated\nToroidal Metasurface Sensor with Broadband\nTerahertz Fingerprint Enhancement for Biochemical Trace Detection

Terahertz\n(THz) trace fingerprint detection is essential for identifying\nthe characteristic biomolecular absorption fingerprints from inherent\nmolecular rotational and vibrational modes. Plasmonic THz resonance\nshows a way to enhance the recognition of biomolecular absorption\nfingerprint spectra. In this research, we experimentally demonstrate\na broadband THz fingerprint metasensor based on a pixelated toroidal\nmetasurface, showcasing excellent capabilities in biochemical trace\ndetection. The design employs mirrored asymmetric double split-ring\nresonators to excite the toroidal resonance with a high quality (Q)\nfactor and strong localized field enhancement. This high Q-factor\nresonance exhibits exceptional spectral resolution with spectral resolution\nless than 50 GHz for broadband fingerprint sensing, thereby capturing\ncharacteristic information. More importantly, the design allows for\nlinear modulation of the split-ring resonator radius, which can be\nextended to cover a larger spectral region by adjusting geometric\nparameters to meet multifingerprints detection of various biochemical\nanalytes. Utilizing fingerprint enhancement and multiplexing technology,\nthe metasensor precisely detects trace glucose with a high sensitivity.\nThe introduction of the metasensor significantly enhances the absorption\ncharacteristics of glucose films, demonstrating an outstanding broadband\nfingerprint sensing performance. This high-performance and flexible\nfingerprint metasensor has potential applications in enhanced broadband\nTHz fingerprint sensing, providing a powerful and low-cost approach\nfor advanced biochemical trace detection.