  Line waves are defined as confined edge modes propagating at the interface of
dual electromagnetic metasurfaces that preserve mirror reflection symmetries.
Previous works have theoretically and practically explored these waves, showing
that they occur at microwave regimes and terahertz ranges. It is also
demonstrated that line waves can happen when there is a symmetric resistance
discontinuity from negative to positive values and a uniform surface reactance.
Line waves are of tunable mode confinement, direction-dependent polarizations,
and singular field enhancement. This study presents a graphene patch design and
demonstrates that the line waves associated with this structure can travel in
the optical domain. Our design consists of a graphene metasurface on an epsilon
near zero (ENZ) substrate. While our approach considers both dual reactive
impedances and homogenous reactive ones, we only concentrate on line wave
utilization in a dual-impedance structure.
