A Photonic Crystal Fibre Sensor for the Detection of Biochemical Analytes With Superior Sensitivity

In this work we present a numerical study and experimental realization of a new, simple and highly sensitive surface plasmon resonance (SPR) biosensor with photonic crystal fiber (PCF). We have improved the performance of our sensor by a strategic patterning of circular air holes within the fiber. All sensor characteristics were evaluated utilizing the finite element method (FEM) based software COMSOL Multiphysics. A plasmonic material, the gold (Au) layer, surrounded the fiber. Finally, after optimizing all parameters of the fiber, we achieved a maximum amplitude sensitivity (AS) of 2202.64 RIU ^− 1 and wavelength sensitivity (WS) of 140,500 nm/RIU and a maximum sensor resolution of 7.12 × 10 ^− 7 for wavelength and 4.54 × 10 ^− 4 for amplitude. Furthermore, the maximum figure of merit (FOM) achieved is 2341.67. Fabrication tolerance limits of the sensor are ± 5% for the gold layer variation and ± 2.5% for the air holes, and the overall biochemical analyte sensing range is between refractive indices 1.31 and 1.40. We expect this SPR based PCF biosensor to have better sensitivity and utility in the detection of unknown analytes, and for medical diagnosis.