Detection of Toxic Gases Based on Refractive Index Sensor for Gas-Sensing Applications

This paper demonstrated a sensor device based on metamaterial in the terahertz region for sensing and detection of toxic gases in pollution air environment. The suggested design comprised of H-typed metallic resonator atop on layer of dielectric and a layer of metallic at the bottom. The simulation results display dual frequencies found at 3.495 THz and 3.945 THz with absorption rate closed to 99%. The suggested sensor is extremely sensitive to the surrounding medium of the RI variation with sensor sensitivity that increases up to 1.41THz/RIU (refractive index unit) while figure of merit (FOM) reaches up to 12.81 RIU⁻¹ lies between 1 and 1.032 RI range. The novelty of the work lies in its novel design, a low cost and highly accurate sensor device, and impressive ability to surpass in gas sensing with extremely high sensitivity. Additionally, the sensor device has the ability of detection of several harmful gases with extremely high sensitivity (S) of 6.47 THz/RIU observed for chlorine (Cl2) gas that was not previously reported in the literature. The suggested work can be footing for designing highly sensitive gas sensors for environmental pollution monitor. The proposed research work can also be significant in other optical sensing applications such as chemical and bio sensing industry applications.