Plasmonic split ring resonator with energy enhancement for the application of bio-sensing and energy harvesting based on the second harmonic generation and multi Fano resonance

Plasmonic characteristic has been implemented for optical enhancement and the Fano resonance is noticed based on the interaction of the dark and bright mode at nano particle and for more enhancement, the second harmonic generation and multi Fano have been suggested. In this paper, we have designed a nano-antenna based on plasmonic, Fano, multi Fano and SHG modes and for this aim we have developed a single ring nano-particle with one and two split ring resonator elements for arousing multi Fano (SHG mode). Exactly, by arousing the Fano and multi Fano modes, the Extinction Cross Section is reduced in comparison with Plasmonic mode based on concentrating energy in the near field. We have shown that the angles of polarization have no effect on the extinction cross-section in multi Fano structure and it is independent of the polarization angle. We have revealed that how the multi Fano would be useful for light trapping and energy harvesting. We have obtained the wider bandwidth for the electric field in comparison with plasmonic and Fano structures which makes our proposed structure useful in energy harvesting applications such as solar cell at higher frequency ranges and an active area for wider bandwidth is achievable. For spectroscopy and optimal imaging, the figure of merit (FOM) is considered as a quality meter for the optical particles. The (FOM) of the external biological materials are compared for all three prototyped plasmonic, Fano and multi Fano structures.