Excitation and tuning of a dual graphene plasmonic wave based on a trapezoidal grating structure.

The independent excitation and tuning of a dual-band graphene plasmonic wave are realized in a hybrid structure that consists of two graphene monolayers placed above and below the trapezoidal grating. Because of the transparency of graphene in the mid-infrared range, the incident light can travel through the first graphene layer to be diffracted by the grating structure and couple its energy to both graphene layers. Numerical simulations are performed using the finite difference time domain method.