Design and Simulation of Nano-Plasmonic Biosensors Open Access
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Abstract of ThesisDesign and Simulation of Nano-Plasmonic BiosensorsDetection of biomolecules in low concentration specimens has a long way to achieve a high precision, low cost and be accessible as a portable device. One proposed method that has the advantage of label free detection of biomolecules is by use of nano plasmonic sensors. Nano plasmonic biosensor is composed of metallic nanoparticle on a dielectric material. In a certain wavelength of the incident light these metallic sensors create a strong localized electric field that is extremely sensitive to an adjacent material, creating a highly sensitive sensor. Producing a higher electric field results in a more sensitive sensor for detection. To our knowledge, there is no study which mentions the appropriate size of the nanoparticles that can produce the highest amount of electric field. In this thesis, Lumerical FDTD software was used to model and compare three different types of nano plasmonic sensors in terms of the created electric field. In addition, a bow tie structure with the optimum size was studied and was able to produce an enhanced field of 90 times of the incident electric field. This, results in an improved sensitivity.Finally, the sensitivity of the bow tie sensor in the proximity of a simulated dielectric with the diameter of 20 nm was examined. The sensor was able to make a 10.5 nm shift in the peak resonance wavelength. The result of this thesis revealed that creating a sensor with a sharp edge generates a more enhanced field with a narrower linewidth in the resonance spectrum.