Detection of wide variety of pathogens by using one-dimensional biosensor based on annular photonic crystal

A novel way of identifying the bacillus anthracis spore and various bacteria cells present in the water samples by means of one-dimensional biophotonic sensor design (PQ)5D(PQ)5 is studied in this manuscript. The proposed biophotonic sensor is designed by associating two 1D annular photonic crystals (APCs) PQ5 through a defect layer D. The alternate cylindrical layers P and Q of both APCs are made up of materials TiO2 and SiO2 respectively. The present study has been carried out in the visible region of electromagnetic (EM) spectrum. First, the proposed biosensor is loaded separately with different water samples containing various bacteria cells and spore into the region marked by defect layer D of the structure. The modified transfer matrix method (MTMM) in cylindrical coordinate system has been used for obtaining simulation results with the help of MATLAB software. The sensitivity of the proposed biosensor varies between maximum of 472.794 nm/nmol/L to minimum of 450.549 nm/nmol/L depending upon the water samples under investigation. Also, the additional parameters like figure of merit (FoM), quality factor (Qf) and limit of detection (LoD) have been evaluated to examine the overall performance of the proposed biosensor. The analysis opens a new pathway to prefer 1D APCs based biophotonic sensors over biosensors made up of 1D planar PCs because APC biosensors are more sensitive than the biosensors based on planar PCs.