Publication

Abstract : A graphene surface plasmon polariton (SPP)-based terahertz (THz) waveguide sensor is presented to realize highly sensitive and selective detection of ethanol. The sensor takes advantage of the tunable plasmonic properties of graphene to create a large resonance shift in the S21 scattering parameter due to ethanol adsorption. It realizes a sensitivity of 3000 GHz/RIU, a figure of merit (FOM) of 53.57 RIU-1, and a limit of detection (LOD) of 0.0187 RIU. These performance parameters are supported by a broad full width at half maximum (FWHM) of 56.01 GHz, which allows for precise identification of small refractive index changes. The variation in effective refractive index is continuously monitored, reaching a low detection threshold without allowing significant signal loss. Such high sensitivity and resolution justify the effectiveness of the sensor for real-time, label-free, and non-invasive detection of minor dielectric changes. The proposed graphene-based plasmonic THz platform is of high promise for application in biomedical diagnostics, environmental monitoring, and industrial quality control, thus establishing a solid ground for the realization of next-generation sensing devices