Plasmonic couplings in split-ring resonators by electric excitation

Abstract

We introduce the symmetric and asymmetric coupling between two geometry-different split-ring resonators (SRRs) with dissimilar resonance frequencies and quality factors. An additional sharp transmission peak is excited as the strong coupling occurs between a narrow subradiant resonance and a broad superradiant resonance by examining the spacing of two SRR constituents. The mechanism of such induced transparency is elucidated well by the suppression of induced currents within the SRR element with a lower quality factor. Finally, the excitation of asymmetrically coupled resonance (ACR) is further associated with remarkable confinement of electromagnetic field on nanoscale, providing a dramatically sensing performance due to its pronounced sensitivity and a characteristic of sharp bandwidth.