High-Q metamaterials based on cavity mode resonance for THz sensing applications

Inspired by the development of terahertz (THz) technology, the demand for THz sensors with high quality and high sensitivity is significantly increasing. In this study, one-dimensional metallic metamaterials based on cavity mode resonance are proposed for sensing applications in the THz regime. Owing to the strong energy concentration in the cavity, metamaterials with a high quality factor were obtained. Thus, the presented device not only achieved narrowband selective absorption but also exhibited excellent refractive index sensing with high sensitivity, figure of merit, and quality factor. The physical mechanism was verified by comparing the simulation results with that of the coupled mode theory. The polarization dependence of absorption and dual-band sensing, which can be actively tuned by the broken symmetry between two adjacent units, were also discussed. Consequently, this study may open up new avenues for the development of biosensing and imaging applications.