Investigation into Micro-Polishing Photonic Crystal Fibers for Surface Plasmon Resonance Sensing

In this work, we propose and demonstrate a micro-polishing-fiber (MPF)-based surface plasmon resonance (SPR) sensor. The structure of the sensor is simple and consists of three layers of regular air holes and two small air holes. The sensitivity seldom depends on the sizes of the air holes, which leads to a sensor with high structure tolerance. A tiny polishing depth ensures the mechanical strength of the polished fiber. There are three decisive factors for mass production and application of the sensor. A thin layer of indium tin oxide (ITO) film is applied to the polished surface to excite plasmonic interactions and facilitate refractive index (RI) detection. The SPR sensor is designed and analyzed by the finite element method (FEM), and optimized in terms of the air holes' diameter, the ITO film thickness, and the core-to-surface interval. In the wide detection range between 1.32 and 1.39, the wavelength sensitivity can reach up to 11,600 nm/RIU. The MPF-SPR sensor exhibits great potential in the fields of optics, biomedicine, and chemistry.

Automated summary

In this study, a micro-polishing-fiber-based surface plasmon resonance (MPF-SPR) sensor is proposed and demonstrated. The sensor has a simple structure and high sensitivity, making it suitable for mass production. By applying an indium tin oxide (ITO) film on the polished surface, plasmonic interactions and refractive index (RI) detection can be achieved. The sensor exhibits a high wavelength sensitivity in a wide detection range, making it promising in the fields of optics, biomedicine, and chemistry.