Electromagnetically Induced Transparency Based on Cascaded π-Shaped Graphene Nanostructure

We demonstrate a cascaded π-shaped graphene nanostructure and investigate its transmission properties which could realize electromagnetically induced transparency (EIT). We also explore the influence of the distance between two π structures and the position of the top dipole strip on the EIT phenomenon, while the results show that when the distance reduces, there exhibits a small change of the transparency window as well as the intensity of this phenomenon. However, the window emerges and becomes stronger as the top dipole antenna moves from left to right. Moreover, the first transmission dip becomes stronger with the shift of the top dipole antenna while the second dip gets weaker. In addition, we design a more compact nanostructure and this structure could also achieve EIT. What is more, a tunable transmission window could be obtained through changing the Fermi energy of graphene, as well as a large group delay. This work has applications in biosensing, photonics, and optical filters.