L-Valine solution sensing based on fano resonance of terahertz metasurface sensor

• Published in: Optics communications 2025-01, Vol.574, p.131166, Article 131166
• Main Authors: Zhou, XinLi, Shu, Jingyi, Hao, Jixuan, Zhao, Guozhong
• Format: Article
• Language: English
• Subjects: Fano resonance; l-valine; Metasurface; Sensor; Terahertz
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2024.131166

A terahertz metasurface sensor with the asymmetric double metal crosses structure is presented. By adjusting the position of vertical bar to generate Fano resonance, the dipole radiation can be greatly suppressed, thereby reducing the ohms and radiation losses of metal and enabling the sensor to achieve a high quality factor (Q factor). A simulation analysis using CST software revealed that the Q factor of Fano peak and Fano dip can reach 25 and 51, respectively. Furthermore, the sensitivity of Fano peak can reach up to 319 GHz/RIU when the thickness of the coating layer is 12.5 μm. Experimentally, a solvent mixture of water and glycerol with a volume ratio of 2:8 is utilized. The lower limit of detection by this method to detect the concentration of l-Valine solution is 5 mM. The concentration sensitivity of l-Valine solution can be quantified at 1.92 GHz/mM. •A terahertz metasurface sensor with the asymmetric double metal crosses structure is presented. The lower limit of detection by this method to detect the concentration of l-Valine solution is 5 mM.•Compared to the sensors mentioned earlier, this sensor has a simpler structure: only four gold bars, reducing the complexity of preparation and enhancing its practicality.•In order to reduce the absorption of terahertz waves by water, a mixed solution of water and glycerol is used as a solvent to prepare solutions of different molar concentrations of l-Valine.