Multi Fano Resonance-based Plasmonic MIM Nanosensor for Label-Free Virus Detection

Plasmonics-based sensors have grown more popular in the biosensing sector because of their label-free detection feature, which not only makes the sensor easier to use but also eliminates the need for numerous antibodies, which is a requirement for enzyme-linked immunosorbent assays. In this paper, a plasmonic-based refractive index sensor is proposed consisting of a linear rectangular waveguide coupled with a semi-ring arc and a microring resonator on both sides separated by a coupling distance. The Finite Difference Time Domain method is used to study the transmittance characteristics of the sensor. The transmittance curve displays Quintuple Fano resonances, which show sensitivity of 1000, 1184, 1290, 1914, and 2372.1 nm/RIU at 1.037, 1.211, 1.323, 2.051, and 2.383 μm, respectively. Further investigation is carried out by varying structural and geometrical parameters, such as the microring resonator's radius and the coupling distance between the semi-ring arc and the microring resonator, which may arise due to fabrication intricacies. The performance of the sensor is investigated using the Figure of Merit, Q factor, and Detection limit producing a value of 30.41 RIU−1, 30.2, and 0.0328, respectively. The proposed sensor is further examined for its potential use in the detection of HSV, influenza A, HIV, and M13 Bacteriophage viruses.