Scattering of quasistatic plasmons from one-dimensional junctions of graphene: Transfer matrices, fresnel relations, and nonlocality

We consider eigenmodes of one-dimensional quasistatic plasmons in periodic graphene structures with junctions of three different types. From the numerical solutions of Maxwell's equations, we reconstruct the transmission and reflection coefficients for single junctions, which are in perfect agreement with the available analytical results. Using our method, we calculate reflections from the double-junction structures and compare them with the semiphenomenological transfer-matrix approach based on the corresponding single-junction solutions. Limitations of the latter approach in designing plasmon resonators and waveguides based on graphene or other two-dimensional conducting materials are discussed.