Design of a 1D PhC biosensor with enhanced sensitivity based on useful features provided for the detection of waterborne bacteria

Abstract

Abstract In this article, we propose a one-dimensional photonic crystal (1D-PhC) biosensor design to detect water-borne bacteria such as Shigella, Vibrio cholera, Salmonella, and E. coli. The theoretical reflectance spectrum of a 1D-PhC and the sensitivity of types of bacteria such as Shigella flexneri, Salmonella, E. coli, and Vibrios cholera are investigated by using the transfer matrix method and MATLAB software. The impact of incident angle and central wavelength on the performance and sensitivity of biosensors are studied. The suggested sensor's sensing process is dependent on variations in the refractive indices of different species of bacteria. The variation in the central wavelength, angle of incidence, the sensitivity of the proposed structure, and other parameters such as full width at half maximum, quality factor, damping ratio, and detection limit can be enhanced. The obtained average sensitivity of our design has a value of 4073 nm/RIU at optimum conditions of defect layer thickness and incident angle. Also, the proposed biosensor design exhibits a high quality factor value of 10996.2165 and a low detection limit value of $$0.44607 \times \,10^{ - 5}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>0.44607</mml:mn> <mml:mo>×</mml:mo> <mml:mspace/> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> RIU.