Structural optimization of a multi-graphene-layer SPR-PCF sensor employing tri-resonant modes

This article explicates the performance of a surface plasmon resonance (SPR) built upon photonic crystal fiber, employing several graphene layers as the singular plasmonic material. The integration of several graphene layers, rather than a monolayer, results in unique triple SPR peaks at three separate resonant frequencies. Simulation results exhibit that this sensor possesses a peak wavelength sensitivity of 4000 nm/RIU in addition to a peak amplitude sensitivity of −1651.38RIU −1 in the y -polarization after optimizing structural parameters. A maximal figure of merit of 200RIU −1 can be reached while preserving the unique triple surface resonance, with the highest linearity R 2 reaches 0.9969, confirming the sensor’s capacity to detect unknown analytes in all three resonant trendlines. The suggested design features a sensor length of up to 14.93 µm, which corresponds to the third resonant mode, and a detection range from 1.54 to 1.64. In addition, a parameter termed Euclidean sensitivity (ES) has been introduced, which takes into consideration both the resonant wavelength and the confinement loss peak difference. The highest achievable ES is calculated to be 2.448 G.U. The suggested sensor, with high sensitivity and a wide detection range at an exceptionally high RI, can open up an innovative viewpoint for a wide variety of chemical and biological analyte detection and broadband applications.