A Hybrid Terahertz Metamaterial Sensor Using a Hexagonal Ring Resonator with Bio-medical Applications

In recent years, novel terahertz (THz) metamaterial sensors are being actively explored by the research community. These structures absorb the incident THz waves, and their absorption spectra shift with the change in the physical parameter. In this paper, a terahertz metamaterial absorber is proposed for sensing both the temperature and the refractive index of the surrounding medium. The unit cell of the proposed structure consists of a concentric hexagonal ring resonator (CHRR) on an indium antimonide (InSb) substrate. The proposed sensor detects the changes in the refractive index with a sensitivity of 1.045 THz/RIU at room temperature, and it can detect the temperature of the surrounding medium having unity refractive index, with a sensitivity of 3.71 GHz/K. It also offers a near-unity absorption of 99.93% at 1.93 THz when the temperature is 300 K, and the refractive index of the surrounding medium is unity. Due to the simple design and dual-sensing capabilities, the proposed sensor can have profound bio-medical applications.