Investigation of ultra-sensitive wave theory based fiber optic biosensor for the detection of Bilirubin using BG beam

This study presents an analytical investigation of a wave theory-based fiber optic biosensor that uses a Bessel-Gauss (BG) beam for the detection of bilirubin. The sensor design consists of an unclad multimode fiber featuring a 100 μm core diameter, coated with a 90 μm layer of bilirubin that functions as the sensing medium. A wave theory approach is employed to analyze high-order modes within the optical fiber, aiming to support theranostic applications in hyperbilirubinemia. The sensor exhibited sensitivities of 0. 75671 dB/nm, 6017. 73 dB/RIU, 24. 65 dB/mm, and 450 nm/g/L, along with a resolution of 1. 66×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−</sup>⁶, which is 10. 16 times greater than that of a sensor utilizing a Gaussian beam as the light source. The proposed design enhances the early screening and clinical diagnosis of hyperbilirubinemia, offering improved sensitivity for accurate bilirubin quantification and clinical diagnosis.