Graphene-Based Refractive Index Sensor With a 1-D Topological Photonic System

A terahertz refractive index sensor, which relies on utilizing the Tamm plasmon polariton and localized topological edge state (TES), is proposed in a 1-D photonic crystal (PC) based on graphene. The proposed sensor structure is an active photonic device due to graphene’s tunable Fermi energy and optical properties. High sensitivity and a high figure of merit (FOM) are the results of the topological protection that allows a perfect zero reflection. Furthermore, the study investigates the sensing performance with various structural and material parameters. This refractive index sensor has the potential to be modified for use in industrial and diagnostic applications.