Design of a New Type of In-Hole Gold-Coated High-Performance Quasi-PCF Sensor Enhanced with Surface Plasmon Resonance.

With the development of aerospace, deep-sea exploration and other technologies, the demand for anti-electromagnetic, high-sensitivity and miniaturized sensors is increasingly urgent. In this paper, a model of a quasi-photonic crystal fiber (Q-PCF) refractive index (RI) sensor enhanced with surface plasmon resonance (SPR) is proposed. A stable gold film with a significant SPR effect is applied to the two identically sized and oppositely positioned air holes of the proposed sensor, and all air holes are filled with analyte. A detailed analysis of the mode characteristics, structural parameters and RI sensing performance of the sensor has been carried out using the finite element method. It has been shown that the maximum sensitivity (S) is 4977.59 nm/RIU in the RI range of 1.35–1.40, corresponding to a resolution (R) of 2.01 × 10⁻⁵ RIU and a figure of merit (FOM) of 160.36 RIU⁻¹. The proposed Q-PCF sensor has unique fabrication advantages and outstanding sensing properties, providing a new idea for biosensing, complex environment monitoring and long-range measurement, and is of great practical value in the field of highly integrated sensing. [ABSTRACT FROM AUTHOR]