High Sensitivity Gold‐Coated Photonic Crystal Fiber Sensor for Blood Component Detection

Photonic crystal fiber (PCF), with its periodic refractive index variations, enables unique light propagation properties such as single-mode guidance and high nonlinearity. This work focuses on the design and simulation of such a PCF, specifically optimized for identifying key blood components like white blood cells (WBC), red blood cells (RBC), plasma, water, and hemoglobin. A nanofilm gold layer is used as a plasmonic substance to enhance sensitivity, increase birefringence, optimize resolution, and maximize transmittance. An analysis and evaluation of the sensor efficacy of this suggested architecture is conducted using the finite element method (FEM). The analytes with high sensitivity to surface plasmon resonance (SPR) are injected into the outermost air holes where silica is serving as the base material. The analysis employed refractive index (RI) values of 1.33, 1.35, 1.36, 1.38, and 1.40 and a wavelength range of 1.1–2.1 µm. Key parameters, including birefringence index (BI), confinement loss, coupling length, power spectrum, transmittance, and power fraction, are meticulously calculated. The maximum birefringence, coupling length, transmittance, and power fraction are \(2.17899\times {{10}^{-}}^{5}\) $2.17899\times {{10}^{-}}^5$ , 71059.43 µm, − 28.8 dB, and 760.1, respectively. Additionally, the sensitivity analysis for wavelength provided significant insights, with the highest recorded wavelength sensitivity reaching 24,340.29 nm/RIU for X-polarization and 24,349.82 nm/RIU for Y-polarization at RI analyte 1.33. This work offers valuable contributions to the design and optimization of PCF-based blood component sensors.