Role of electric currents in the Fano resonances of connected plasmonic structures

In this work, we use finite elements simulations to study the far field properties of two plasmonic structures, namely a dipole antenna and a cylinder dimer, connected to a pair of nanorods. We show that electrical, rather than near field, coupling between the modes of these structures results in a characteristic Fano lineshape in the far field spectra. This insight provides a way of tailoring the far field properties of such systems to fit specific applications, especially maintaining the optical properties of plasmonic antennas once they are connected to nanoelectrodes. This work extends the previous understanding of Fano resonances as generated by a simple near field coupling and provides a route to an efficient design of functional plasmonic electrodes. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

In this study, finite element simulations were used to investigate the far field properties of two plasmonic structures connected to nanorods, revealing a characteristic Fano lineshape due to electrical coupling between the modes. This insight offers a way to tailor the far field properties of these systems for specific applications, particularly in maintaining the optical properties of plasmonic antennas when connected to nanoelectrodes. This work expands on the understanding of Fano resonances generated by near field coupling and provides a pathway to efficiently design functional plasmonic electrodes.