Ultrasensitive dual-band terahertz metasurface sensor based on all InSb resonator

Abstract

Terahertz (THz) metasurface sensors have recently received considerable attention. We report an ultrasensitive dual-band metasurface (DBM) sensor in this work. The reported DBM sensor is a micro-rod periodic structure based on all InSb semiconducting material. The DBM is realized for the dual-band resonance behaviour at 1.911 THz and 1.985 THz. The corresponding Q factor for the DBM sensor is obtained at the higher side, around 174.36 and 181.11 at room temperature (T = 300 K). The geometrical parameters dependency for the resonance frequency of the proposed DBM is analysed and reported. Further, the refractive index sensitivity is observed by varying the surrounding’s refractive index from 1.00 to 1.05 (aqueous glucose solution). It is reported that, at room temperature, the proposed DBM sensor shows a sensitivity of 1800 GHz/RIU and 1900 GHz/RIU at the corresponding resonance frequencies 1.911 THz and 1.985 THz respectively. The temperature sensitivity of the proposed DBM is also explored and reported. Furthermore, the figure of merit (FOM) of the proposed DBM sensor is 164 and 173 respectively at corresponding resonance frequencies. So, the reported DBM structure could also find potential applications in the THz region as sensors, detectors, and other optoelectronic devices.