Propagation of Surface Plasmon Polaritons in Hybrid Waveguide with Metal Cap and Graphene Layer

The propagation of surface plasmon polariton in a hybrid waveguide with metal cap and a graphene layer has been studied in this work. The structure consists of a Si rib on a SiO2 substrate and having graphene layer under the Ag cap on the rib. For this structure, the propagation length of plasmon mode increases when the width and height of graphene layer decrease. The highest propagation length has been found to be 1814 μm with the confinement area about 250 nm2. Thus, a very high figure of merit has been obtained in the order of 106. Finally, the height of Si rib is also decreased to examine the feasibilty of smaller scale fabrication and to increase the robustness of the device.