Highly sensitive all-metallic terahertz metamaterial sensor for biological detection

In this paper, a terahertz metamaterial biosensor based on all-metal medium is studied theoretically and verified experimentally. The sensor unit structure consists of four symmetrical open rings hollowed out on metallic copper. Theoretical simulation results demonstrate that the metamaterial sensor exhibits a transmission peak of 0.948 at a frequency of 0.844THz. Based on the simulation analysis of the working mechanism of the sensor, its sensing performance is investigated. When a thin layer of analyte with a thickness of 20μm and a refractive index of 1 to 1.5 is attached to the surface, the sensor exhibits an extremely high refractive index sensitivity of 484.6GHz/RIU and a better figure of merit (FOM) value of 5.35. The sensor was fabricated on copper foil by laser etching technology. To verify the sensing performance, different concentrations of glucose solutions were tested experimentally. The limit of detection (LOD) of the sensor was 0.758μmol/L for glucose solution. The terahertz metamaterial biosensor proposed in this paper has the advantages of simple structure, high sensitivity and facile fabrication, thereby offering promising prospects for broad applications in the field of biomedical sensing.