Shape trapped-mode resonances in polarization conversion metasurfaces for ultra-sensitive terahertz sensing

High quality factor resonances play a significant role in sensor technology. We excite shape trapped-mode resonances in polarization conversion metasurfaces (PCMs) by introducing resonance cavities gaped by two split elliptical ring resonators (SERRs). The quality factor of the resonances can achieve 370.75, and the resonances are angle-independent and polarization independent. Moreover, the resonance frequencies are sensitive to the change of the refractive index of surrounding with the sensitivity of 6.76×10³nm/RIU. So the proposed metasurfaces have exciting application prospect in plasmonic sensing.