Terahertz-Multiplexed Metallic Metasurfaces for Enhanced Trace Sample Absorption

Many biomolecules exhibit characteristic fingerprint spectra in the terahertz band. This paper describes an optimized detection method using the parametric multiplexing of terahertz metallic metasurface. The method can greatly enhance the terahertz absorption spectra of trace α-lactose analytes by multiplexing geometric parameters of the metasurface. Additionally, the dispersion relationship, electric field distribution, absorptivity and other characteristics of the metal metasurfaces are obtained. The relationship between the thickness of the trace sample, the structural parameters of the device and the enhancement characteristics is investigated. The results demonstrate that the designed terahertz metallic metasurface exhibits high sensitivity and stability in detecting the absorption fingerprint spectrum of biomolecules. The absorption enhancement factor of the 0.1-μm thick α-lactose sample to be tested on the metallic metasurface is about 264 times higher than the direct absorption of terahertz waves by the untreated specimen. The findings of this research offer new ideas and methods for further researches and applications in the field of biomolecule absorption detection.