Optical properties of MIM plasmonic waveguide with an elliptical cavity resonator

Metal–insulator–metal waveguide structure, which has a fascinating feature to confine the signal far beyond the diffraction light is numerically investigated by the finite difference time domain and the finite element methods. In this study, the MIM waveguide is both coupled with a half-elliptical groove (HEG) and an elliptical cavity resonator (ECR), and it can support the propagation of light in the nanoscale regime at the visible and near-infrared ranges. The interaction between these last elements gives rise to Fano resonance modes. Thanks to its interesting characteristics, a high sensitivity value, a factor of merit and interesting value of the group index are obtained for the proposed structure. We show that the transmission of the Fano system and the group index can reach 90% and a value of 63, respectively. We also report an investigation of the influence of the both geometrical HEG and ECR’s parameters on optical properties. Hence, the proposed structure could find a potential for applications in the integrated optical circuits such as optical storage, ultrafast plasmonic switchers, high performance filters and slow light devices.