Plasmonic Analog of Klein Tunneling in Binary Graphene Sheet Arrays

We theoretically investigate the plasmonic analog of the relativistic Klein tunneling processes in systems of two coupled graphene waveguide arrays with spatially varying chemical potentials. By introducing an offset in the chemical potentials of the graphene sheets, a potential step is generated in this platform. Numerical simulations indicate that in the graphene array with λ = 10 μm, d = 70 nm, and μc∼ 0.15 eV, the surface plasmon polaritons exhibit non-unity transmission (up to 50%) across the potential step at the interface that depends on both angle and potential, which is analogous to the Klein tunneling effect. Analytical calculations of the transmission rate of Klein tunneling in these structures have been derived and are consistent with the simulations. This work provides a robust platform for controlling light propagation at deep-subwavelength scales and emulating relativistic quantum phenomena in photonic systems.