Plasmonically Induced Absorption and Transparency Based on MIM Waveguides With Concentric Nanorings

In this letter, the metal-insulator-metal plasmonic waveguides shoulder-coupled two concentric nanorings are investigated both numerically and theoretically. Based on the three-level system, the extreme destructive interference between bright and dark resonators gives rise to the distinct plasmonically induced absorption response with the abnormal dispersion and novel fast-light feature. By the same principle, the dramatic plasmonically induced transparency effect with slow-light characteristic is obtained in the waveguide-resonator system with side-coupling configuration. All simulated results are confirmed by the coupled mode theory. Proposed structures will open a new avenue for controlling the speed of a light signal in ultra-compact integrated devices.