A high-performance biosensor design for waterborne bacteria detection based on one-dimensional photonic crystal

One of the global challenges nowadays is detecting and removing the waterborne bacteria from drinking water. In this work, we propose a one-dimensional photonic crystal based on Si/SiO2 layers containing a defect layer in the middle of the structure to detect waterborne bacteria. The findings have been formulated using the transfer matrix method, where the sensor mechanism is based on the variation of the refractive index of different bacteria samples from that of pure water. The impact of various parameters like the angle of incidence, the thickness of the defect layer, and the number of periods of the structure are studied to find the optimized condition. The sensor shows high sensitivity of 2486.57 nm RIU that can detect minimal changes of defect mode peak inside the photonic bandgap of the transmission spectra. Other performance parameters such as the quality factor (5455.70), figure of merit (6262.31 RIU-1), and limit of detection (2.72x10(-05) RIU) have also been calculated to get a deeper understanding of the sensor's capabilities. Therefore, the simplicity and excellent performance make our design efficient for any sensing application as well as fabrication process.