Tunable Electromagnetically Induced Transparency-Like in Plasmonic Stub Waveguide with Cross Resonator

An analog of electromagnetically induced transparency (EIT) is investigated in a metal-insulator-metal (MIM) waveguide structure consisting of a stub waveguide and a side-coupled cross resonator. The transmission properties of this plasmonic MIM waveguide structure are numerically studied by the finite element method. The results show that there are double EIT-like phenomena as well as multiple EIT-like peaks in the transmission spectra by adding another stub. The transparency windows not only can be manipulated by changing the coupling distance between the stub and the cross resonator and the length of the horizontal and vertical cavity but also show a red shift with the increase of the refractive index n of the medium in the cross resonator. The designed plasmonic MIM waveguide structure is able to serve as a filter with a transmission rate of over 80 % and is easy to detect the refractive index of the filled media in the cross resonator, which indicates the potential applications in filtering and sensing.