Design of an unclad single-mode fiber-optic biosensor based on localized surface plasmon resonance by using COMSOL Multiphysics 5.1 finite element method.

This study proposed an unclad optical fiber biosensor based on the localized surface plasmon resonance phenomenon and operating at 650 nm using COMSOL Multiphysics 5.1 finite element method (FEM). Gold nanoparticles (50 nm thickness) were coated on the middle portion of the unclad fiber. Air, water, blood plasma, liver tissue, colon tissue, and pentanol (C5H11OH) were used as analytical layers with 3 µm. The sensor serves as a theoretical foundation for experimental research. The blood plasma had the highest sensitivity with a sensitivity of 10,638.297 nm/RIU and a resolution of 9.410-6RIU. The proposed sensor is a promising candidate for a low-cost, simple-geometry biochemical sensing solution.