Extraordinary sensitivity enhancement by metasurfaces in terahertz detection of antibiotics

• Published in: Scientific reports Vol. 5; no. 1; p. 8671
• Main Authors: Xie, Lijuan, Gao, Weilu, Shu, Jie, Ying, Yibin, Kono, Junichiro
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.03.2015; Nature Publishing Group
• Subjects: 140/125; 639/624/1107/510; 692/499; Anti-Bacterial Agents - analysis; Antibiotics; Chemical perception; Chemoreception; Electric fields; Food quality; Food safety; Humanities and Social Sciences; Kanamycin; Kanamycin - analysis; multidisciplinary; Science; Silicon; Spectroscopy; Spectrum analysis; Sulfates; Surface Properties; Terahertz Spectroscopy
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep08671

We have detected trace amounts of molecules of antibiotics (kanamycin sulfate) dispersed on metasurfaces with terahertz (THz) spectroscopy. Utilizing the extraordinary optical transmission resonance of an array of square-shaped slits on a silicon substrate at ~0.3 THz, we were able to monitor varying concentrations of kanamycin sulfate as low as ~100 picogram/L. In contrast, the lowest detectable concentration of kanamycin sulfate on silicon without any metallic structure was ~1 gram/L. This dramatic ~10 10 times enhancement of sensitivity is due to the near-field enhancement of THz electric fields by the metamaterial structure. This result thus demonstrates the power and usefulness of metamaterial-assisted THz spectroscopy in trace molecular detection for biological and chemical sensing as well as for food product quality and safety inspection and control.