High confidence plasmonic sensor based on photonic crystal fibers with a U-shaped detection channel

In order to improve the performance of optical fiber sensing and expand its application, a photonic crystal fiber (PCF) plasmonic sensor with a U-shaped channel based on surface plasmon resonance (SPR) is proposed. We have studied the general influence rules of structural parameters such as the radius of the air hole, the thickness of the gold film and the number of U-shaped channels using COMSOL based on the finite element method. The dispersion curves and loss spectrum of the surface plasmon polariton (SPP) mode and the Y-polarization (Y-pol) mode as well as the distribution of the electric field intensity (normE) under various conditions are studied using the coupled mode theory. The maximum refractive index (RI) sensitivity achieved in the RI range of 1.38-1.43 is 24.1 mu m RIU-1, which corresponds to a full width at half maximum (FWHM) of 10.0 nm, a figure of merit (FOM) of 2410 RIU-1 and a resolution of 4.15 x 10(-6) RIU. The results show that the proposed sensor combines the SPR effect, which is extremely sensitive to changes in the RI of the surrounding medium and realizes real-time detection of the external environment by analyzing the light signal modulated by the sensor. In addition, the detection range and sensitivity can be extended by adjusting the structural parameters. The proposed sensor has a simple structure with excellent sensing performance, which provides a new idea and implementation method for real-time detection, long-range measurement, complex environment monitoring and highly integrated sensing, and has a strong potential practical value.

Automated summary

To improve optical fiber sensing performance and broaden its application, a photonic crystal fiber (PCF) plasmonic sensor with a U-shaped channel based on surface plasmon resonance (SPR) is proposed in this study. The influence rules of structural parameters, such as the radius of the air hole, the thickness of the gold film, and the number of U-shaped channels, were investigated using COMSOL and the finite element method. The dispersion curves, loss spectrum, and electric field intensity distribution were studied under various conditions. The proposed sensor achieved a maximum refractive index sensitivity of 24.1 mu m RIU-1 in the RI range of 1.38-1.43, with a FWHM of 10.0 nm, a FOM of 2410 RIU-1, and a resolution of 4.15 x 10(-6) RIU. The sensor combines the highly sensitive SPR effect and allows for real-time detection of the external environment. The detection range and sensitivity can be increased by adjusting the structural parameters. The sensor has a simple structure and excellent performance, providing a new approach for real-time detection and highly integrated sensing.