A novel plasmonic elliptical nanocluster and investigating Fano response in - and T-shaped arrays

Fano resonance has been considered especially in nanostructures for energy enhancement and creating hot spots in nanoparticles based on plasmonic properties. In this paper, a novel arrangement of elliptical nanoantenna has been noticed for improving the electric field and energy enhancement in hot spots for mid-infrared range. For this, elliptical cylinders and elliptical rings are developed for dark mode by the concentration of plasmonic charges in a limited area, and the interaction between bright and dark mode has been used for the Fano shape of the extinction cross section. The combination of dipole arrangement has been implemented based on elliptical hollow cylindrical particles with various inner radios for arousing the Fano resonance. Finally, - and T-shaped models are studied for Fano resonance, and the electric fields are compared in all cases. Exactly, this study is important for two main reasons: (1) it shows how we can control the extinction cross section and (2) it shows that by distortion for linear array the Lorentzian shape is changed to Fano shape.