A rectangular hybrid plasmonic waveguide (HPW) structure has been proposed to detect the presence of harmful benzene gas in the surroundings, specifically for oil/gas and other relevant industries. The proposed sensor has a simple and unique design, which has three successive layers of metal (silver) atop underlying layers of silicon ( \(\text{Si}\) ) and silica ( \({\text{SiO}}_{2}\) ), wherein the analyte can be confined inside the interstices of the metal layers. The proposed sensor facilitates the fabrication owing to its simple design and operates mostly within the near-infrared (NIR) wavelength range of ~ 1500–1550 nm. To arrive at the efficient sensor structure, both 2D and 3D designs have been utilized, and the numerical approach, based on the finite element method (FEM), has been adopted for the investigations. This has been accomplished by altering the different dimensions of the proposed HPW-based sensor and examining the attributes of propagating fundamental hybrid modes. The prime performance metrics are the confinement factor, propagation length, wavelength sensitivity, figure of merit (FOM), etc. The level of wavelength sensitivity has been achieved as ~ 127.91 nm per refractive index unit (RIU). The necessary fabrication steps have illustrated the ease of fabrication of the proposed sensor structure. A comparison with recent research has demonstrated the efficacy of the proposed sensor, which can be further refined to detect more hazardous gases/chemicals in the environment.
