A highly optimized and sensitive bowtie shape-based SPR biosensor for different analyte detection

Abstract

With advancements in photonic technologies, photonic crystal fibers (PCFs) have become crucial components in developing highly sensitive and efficient biosensors. This paper presents an optimized bowtie-shaped PCF biosensor that leverages surface plasmon resonance (SPR) phenomena for enhanced refractive index (RI) sensing. The proposed design uses an external sensing mechanism to effectively characterize performance across an RI range of 1.32 to 1.44. Fabrication is simplified by selecting a large pitch and gold layer height, while performance is enhanced by increasing pitch size, improving the gold layer, and optimizing air hole diameter. Simulations performed using the finite element method in COMSOL Multiphysics v5.4 demonstrate an impressive wavelength sensitivity (WS) of 143 000 nm per RIU and an amplitude sensitivity (AS) of 6242 per RIU. The sensor also exhibits a high resolution of 6.99 × 10⁻⁷ RIU and maintains excellent full width at half maximum (FWHM) characteristics, resulting in a very high figure of merit (FOM) of 2600, indicating superior performance. These promising results suggest that the optimized bowtie-shaped PCF biosensor can be effectively applied to detect a wide range of biological and chemical substances with high precision and sensitivity.