Plasmon-induced transparency effect in metal-insulator-metal waveguide coupled with multiple dark and bright nanocavities

We used bright and dark nanocavities coupled to a metal-insulator-metal waveguide to realize a plasmonic analogue of electromagnetically induced transparency (EIT) in integrated plasmonics. The bright nanocavity is directly coupled to the waveguide, while the dark nanocavity is achieved with the help of evanescent coupling. The numerical simulation shows a typical EIT-like line in the transmission spectrum. Using the model of EIT effect in a three-level atomic system, this phenomenon is well explained. Adding the number of dark nanocavities, we get multiple transparent peaks in the transmission spectrum of plasmon-induced transparency (PIT) effect, and we can realize control of the PIT effect by changing the geometric parameters of the plasmonic structure.