Strong coupling between two plasmonic cavities based on metal-insulator-metal structure

摘要

We investigate the strong coupling phenomenon between a circular cavity and a rectangular cavity based on a metal-insulator-metal (MIM) structure. Finite difference time domain method is employed to well describe the strong coupling phenomenon and the simulation results show that two splitting peaks are observed in our proposed structure, while only one resonant peak is found in MIM structure involving only a circular cavity. The coupling between the circular cavity and the rectangular cavity is manipulated by the geometry of the cavities and the symmetry of the whole structure. An asymmetric lineshape of the transmission spectrum is observed with a narrow linewidth and a deep valley, which has potential applications in plasmon sensor.