Development and Modelling of a Photonic Crystal Fiber Sensor for Detecting Harmful Chemicals in Polycarbonate Plastics

This study presents the development and modeling of a photonic crystal fiber (PCF) sensor designed for detecting harmful chemicals in polycarbonate plastics. The sensor features a wheel-shaped PCF structure with a floral pattern in the initial cladding layer. The focus is on two significant chemical compounds commonly found in plastics, bisphenol A (BPA) and bisphenol S (BPS). The individual sensitivities of the sensor to these compounds are measured, achieving relative sensitivities of 90.716% for BPS and 84.688% for BPA. The effective refractive indices for BPS and BPA are found to be 1.499 and 1.550, respectively. Additionally, the study analyzes confinement loss and nonlinearity of the proposed structure when exposed to these compounds, demonstrating low confinement loss and high nonlinearity, which are desirable attributes for sensing applications. The octagonal floral structure of the PCF sensor shows potential for a variety of applications, including chemical and biochemical sensing and nonlinear optics. The propagation characteristics and performance of the wheel-shaped hollow-core PCF have been thoroughly analyzed within the wavelength range of 1.5 μm to 2.5 μm. The sensor, utilizing silica as the background material, exhibits high sensitivity and low confinement loss. The analysis indicates that increasing the number of air holes in the cladding and enlarging the core size, where electromagnetic waves interact with the analyte, can further enhance sensitivity and detection accuracy with minimal losses. The PCF sensor offers real-time, label-free detection of chemical compounds with a high birefringence of -9.594×10-5, a highest refractive index (RI) of 1.550, and an effective area of 4.373×10-12 m2 for BPS at 1.2 μm. The proposed method yields negligible confinement loss, making it suitable for applications in optical fiber sensing, optical waveguides, and various photonic devices.