Design and simulation of four stage antiresonant reflecting plasmonic microring biosensor for detection of Ecoli Bacterium-O157 in water

In this paper, a combined biosensor from anti-resonant reflecting plasmonic waveguide (ARPWG) and Vernier-based microring resonator was designed. The Finite Difference Eigen solver method was used for ARPWG and two fundamental modes, including a pure mode and a bound surface plasmon polariton mode in the vicinity of the metal-dielectric interface, were obtained at the visible wavelengths by varying the refractive index of the superstrate layer. Then, the ARPWG applied in the four stage microresonator for achieving a free spectral range of 150 nm. The optical transfer function of this sensor was derived using the delay line signal approach and Mason rule. Lastly, the designed sensor was used for detection of Ecoli-O157 bacterium in drinking water. The sensitivity of 140.4 nm/RIU and 475.9 nm/RIU and the detection limit of 1.14 ×10-4 RIU and 3.36 ×10-5 RIU were realized for TMo and TM1 modes, respectively. The Advantages of the proposed sensor rather than conventional biosensors are in fast detection, high sensitivity and resolution, microscale size, low cost and the ability to integrate into the available electronics systems