Perfect-absorption, High-sensitivity, and Low-thickness THz Gas Sensor Based on Tamm Plasmon Polaritons

In this paper, an ultra-high sensitivity and low-thickness gas sensor based on the excitation of Tamm plasmon polaritons (TPPs) and Fabry-Perot resonances in the frequency range of 0.1 to 1THz is presented. The sensor consists of a graphene sheet, a spacer layer, a gas tank, and a one-dimensional dielectric-metallic photonic crystal (DM-PhC). The transfer matrix method is used to evaluate the effects of various parameters, including the presence of the graphene sheet, the number of periods, the chemical potential of graphene, and the thickness of the layers, on the absorption spectrum of the sensor. The simulation results reveal that the presence of the graphene sheet is mandatory for exciting TPPs. Additionally, the use of a DM-PhC enhances the absorption and reduces the thickness of the sensor. The absorption and sensitivity of the sensor can reach high values of 99.98% and 0.887THz/RIU for adjusting the geometrical parameters. The sensor benefits from high absorption and sensitivity, fabrication-friendly structure, tunability by the chemical potential of graphene, and low thickness. The proposed sensor can find many applications in industrial fields.