Optimization of Strong Coupling between Dipole and Quadrupole Modes Through Variations in Plasmonic Nanodimers

Abstract

It is highly desirable to form compact and easily controllable optical systems based on simple units to achieve the manipulation of strong coupling to huge intensity accompanied by wide spectral splitting and fast energy transfer, which is particularly important for promoting the further development of miniaturized plasmonic photodevices. Here, we realize the optimization of strong coupling between dipole and quadrupole modes in variable plasmonic nanodimers based on the improvement of effective spatial overlap of electric field distribution and high excitation efficiency of quadrupole mode, as well as expansion of coupling region and enhancement of radiation field, caused by the change of the unit structure and arrangement. Specifically, we demonstrate the Rabi splitting and anticrossing behavior in nanodimers as well as time-domain oscillations of energy exchange, ultimately obtaining the maximum Rabi splitting of 365 meV and the interaction potential of 198 meV, and the shortest energy exchange period of 11.5 fs.

Keywords: plasmonics nanostructure, strong coupling, rabi splitting, energy exchange, lifetime