Design and Analysis of a Graphene Magneto-Plasmon Waveguide for Plasmonic Mode Switch

In this paper, we design and investigate a graphene magneto-Plasmon waveguide for plasmonic mode switch application. First, an analytical model based on effective index method is presented to extract waveguide properties, such as effective index, effective guide width, cutoff wavelength, and the number of guided modes. We then verify the results with the finite element method. Due to the strong magneto-optical activity of graphene under an external magnetic field, waveguide properties can be widely tuned magnetically. Here, using a combination of several parameters, including chemical potential, magnetic field, and structure width, we manipulate the waveguide properties, such as mode confinement and the number of guided modes in order to achieve desired functions. The results demonstrate that the proposed structure acts as a mode switch device. Namely, for a given chemical potential and wavelength, the guided modes are controlled by the magnetic field. Moreover, we show that the waveguide becomes non-reciprocal in the presence of a magnetic field, which enables the structure to act as a plasmonic isolator and circulator.