Design and Analysis of a highly sensitive open trapezoidal channel PCF-based Plasmonic Refractometric Sensor

Abstract This study introduces a highly sensitive trapezium-shaped PCF based on an SPR refractometric sensor with unique design features. The structure of a sensor was designed and analyzed using COMSOL Multiphysics v5.6 based on Finite Element Method (FEM) with a focus on investigating the influence of various geometric parameters on its performance. The two channels were coated with a metallic gold layer to provide chemical stability, and a thin layer of TiO₂ improved the gold's adhesion to the fiber. The findings indicate that the proposed sensor achieves maximum amplitude and wavelength sensitivities of 1,779 RIU⁻¹ and 30,500 nm/RIU, respectively, with corresponding resolutions of 3.28×10⁻⁶ RIU for analyte RI sensing ranging from 1.30 to 1.42, operating in the visible to near-infrared region with a wavelength range (500 nm-1400 nm). The highly sensitive sensor provides wide potential for RI detection in chemical and biological sensing.