Terahertz Metasurface With High-Q Fano Resonance for Bio-Sensing

High-quality factor Fano resonances offer exceptional potential for the creation of ultrasensitive refractive index sensors owing to their capacity to facilitate robust interactions between electromagnetic waves and analytes. In this article, we introduce a general approach for designing sensitive metasurface sensors leveraging high-Q Fano resonances. The metasurface, composed of metallic strips varying in length, produces the characteristic Fano line shape through the interference of bright and dark modes. Our findings reveal a remarkable sensitivity of up to 0.473 THz/RIU at 2.37 THz, with a maximum resonance Q value attainment of 38.12. The tunable properties of Fano resonances can be fine-tuned by adjusting geometric parameters. As a demonstration of the practical applicability of these high-Q resonances, we conducted experimental assessments of the metasurface sensor's performance in detecting the concentrations of bovine serum albumin and glucose. Notably, both the resonance frequency and amplitude undergo significant changes in response to increasing analyte concentrations. This allows for rapid and precise determination of both the concentration and molecule type based on observed frequency shifts. Our strategy paves the way for the design of ultrasensitive real-time sensors operating in the terahertz regime.