Graphene-based tunable plasmon-induced transparency utilizing circular and two rectangular gold rings in the near-infrared spectrum

A plasmonic induced transparency utilizing one circular and two rectangular gold rings in silicon substrate covered by a monolayer graphene sheet is investigated numerically and theoretically in the near infra-red spectrum. Three-dimensional finite difference time domain (3D-FDTD) simulations are employed to extract the set of geometrical parameters to achieve a 1200-2200 nm transparency window. By sweeping the Fermi level of the graphene, we study transmissions, phase shifts, and group delays of the proposed structure. The group delay was about 0.02 ps (ps) for 0.6 electron-volt(eV) Fermi level, and it showed the capability of slow light applications. Moreover, a linear modulation index of 11% was achieved at lambda = 1550 nm for 4-layer graphene. The results offered that the plasmonic induced transparency (PIT) effect may be used in the slow-light devices and active plasmonic modulation in the communication wavelength.

Automated summary

In this study, a plasmonic induced transparency effect was achieved in the near infra-red spectrum by utilizing one circular and two rectangular gold rings in a silicon substrate covered by a monolayer graphene sheet. This effect can be used for slow-light devices and active plasmonic modulation in communication.