High Sensitivity Core-Shell Structure (CSS)-Based Fiber Sensor for Monitoring Analytes in Liquids and Gases

A compact and robust mid-infrared refractive index-based microstructured fiber sensor with high sensitivity is developed for monitoring analytes in liquids and gases. Resonant core-shell elements facilitate its exceptional performance. The theory underpinning them is explained, and the evolution of the fiber structure is presented. The material choices and details of the microstructure leading to its optimization are described. Simulation results demonstrate that the optimized fiber sensor can readily detect refractive index variations in the range from 1.0 to 1.41 and that its wavelength sensitivities are 2510 and 4303 nm/RIU for analyte detection, respectively, in gases and liquids. It is an excellent candidate for environmental monitoring applications.