Fano-resonance-inspired terahertz metamaterial sensor for refractive index sensing applications

This paper proposes a metamaterial THz sensor based on Fano resonance, which shows high sensitivity and a quality factor for index sensing. The proposed structure features a simple architecture composed of two circular split-ring resonators with different sizes, while structural asymmetry is introduced to generate Fano resonances. Simulation results show that the proposed sensor achieves a sensitivity of 0.151 THz/RIU and a Q-value of 54.5, with an FOM value of 12.6 in the lower THz band. The effect of geometrical parameters on sensing performance is analyzed, and the sensor shows high tolerance to fabrication error of structural dimensions. The proposed design, which enables the detection of small variations in the refractive index via THz spectroscopy analysis, shows potential for biomedicine sensing applications.