X-Shaped Air-Hole Orientation Based Photonic Crystal Fiber Biosensor with Indium Tin Oxide Film

This work presents a theoretical investigation of a simple yet novel photonic crystal fiber (PCF) biosensor, which utilizes principle of surface plasmon resonance (SPR) effect. The numerical characterization was done using the finite element method (FEM) through COMSOL Multiphysics software. As the active plasmonic material Indium tin oxide (ITO) is used at the outer surface of the PCF-based biosensor. The air-holes orientation within the PCF resembles the shape of “X”, which is designed to enhance the phase matching between the core-guided mode and the plasmonic mode. The operating region of the sensor is near-infrared (1400 – 2000 nm), for the analyte refractive index range between 1.32 and 1.36. Wavelength sensitivity of 12,000 nm/RIU and amplitude sensitivity of 231 RIU
⁻¹
is achieved with the high resolutions of 8.33×10
⁻⁶
RIU. The proposed biosensor is suitable for accurate sensing applications of detecting unknown RI in the field of biological analyte detections.