Investigation of defect based 1D photonic crystal structure for real-time detection of waterborne bacteria

We have proposed both symmetric and asymmetric configurations of 1D defective photonic crystal structures, which are designed with an alternate arrangement of MgF2 and PbS for real-time detection of waterborne bacteria such as Escherichia coli, vibrio cholera and shigella flexneri. The transfer matrix method is employed to assay the transmittance and absorption spectrum of the said structures. A substantial shift in position of the resonant peak is noticed, when the defect layer is infiltrated with contaminated water containing different bacteria. The effects of variation in the defect layer thicknesses, angles of incidence and period of the dielectric layer on the sensor performance are thoroughly addressed. An optimum sensitivity of 387.5 nm/RIU, SNR of 79.2, FOM of 1174.24RIU-1, DL of 2.44?10-4RIU and resolution of 0.0881 nm is achieved for asymmetric structure. The aforementioned upshots could open up an avenue for realization of effectual and real-time waterborne bacteria sensor for biophotonics applications.