A novel transmission model for plasmon-induced transparency in plasmonic waveguide system with a single resonator

We investigate the electromagnetically induced transparency (EIT)-like effect in a single rectangle resonator modulated MIM bus waveguide system. A modified transmission model with two branches is proposed to characterize the physics of the two orthogonal electromagnetic modes formed in the resonator. Close agreement between the analytical results and the finite-difference time-domain (FDTD) simulations verifies the validity of the proposed transmission model. In addition, two different three-level systems mimicking the atomic EIT effect are utilized to further clarify the underlying physics of the plasmon-induced transparency (PIT) effect. It is found that better EIT-like shapes and larger values of group index can be achieved in the horizontal excited system (HES) than in the vertical excited system (VES). The results may deepen the understanding of the EIT-like effect and provide a helpful guideline for the control of light in highly integrated optical circuits.