Label-Free Glucose Sensing Using a High-Q Terahertz Metamaterial Absorber

This work presents a highly sensitive terahertz (THz) metamaterial absorber tailored for glucose detection in aqueous environments. The absorber features a multi-resonant structure with four distinct absorption peaks at 2.02, 4.41, 5.06, and 5.39 THz, achieving absorption efficiencies of 99.8%, 99.2%, 96.4%, and 95.2%, respectively. Among these, the 5.06 THz resonance exhibits the highest quality factor of 265, making it ideal for high-resolution sensing applications. To evaluate its biosensing performance, a 1 micrometer thick analyte layer was modeled with refractive index values ranging from 1.3 3 (pure water) to 1.45 (30% glucose solution). The resulting resonance shift yielded a sensitivity of 262.5 GHz/RIU and a figure of merit (FOM) of 7.17, demonstrating the absorber's capability to detect subtle changes in glucose concentration. These results highlight the potential of the proposed design for non-invasive glucose monitoring and other biomedical sensing applications in the THz regime.