Design and analysis of high-Q and high-sensitivity terahertz metasurface sensors

High-quality factor (Q) and high-sensitivity terahertz metasurface sensors have been widely studied in the field of biochemical sensing. However, the large radiation loss of the inductor-capacitor (LC) resonance and dipole resonance commonly used in conventional metasurface sensors limits the metasurface sensor quality factor and transmittance. In this paper, we design an asymmetric double-open metal pair ring of terahertz metasurface sensor to break the symmetry of the unit structure and to excite the electric dipole resonance and the electromagnetic induction-like transparent resonance, which improves the performance of the metasurface sensor. The effects of different structural parameters on the performance of the metasurface sensor are analysed, and the sensing performance of the sensor is improved by optimising the structural parameters. The results show that there are two resonance frequency points of the sensor, the quality factor Q = 385 and the sensing sensitivity S = 302 GHz/RIU for the electric dipole resonance at f₁ = 1.561 THz, and the quality factor Q = 279 and the sensing sensitivity S = 315 GHz/RIU for the electromagnetically induced transparent resonance at f₂ = 1.794 THz, which achieves the high Q high and sensitivity dual resonance sensing.