Reflection and Transmission of Obliquely Incident Graphene Plasmons by Discontinuities in Surface Conductivity: Observation of the Brewster-Like Effect

Scattering of graphene surface plasmons that are obliquely incident on a line discontinuity in graphene surface conductivity is investigated. The analysis is based on a solution of the quasi-static integral equation for surface charge density. It is shown that the reflection coefficient of the graphene plasmons reaches a minimum at a specific angle of incidence that depends on the ratio of conductivities of the two regions surrounding the discontinuity. This effect, which is similar to the well-known Brewster effect, is pronounced for abrupt discontinuities, but becomes weaker as the width of the transition region increases. The results obtained can be used for the design and analysis of devices based on graphene layers with non-uniform conductivity patterns. As an example, an approximate method is presented for obtaining the dispersion relation of waveguide modes in a graphene ribbon.