Prefect Klein tunneling in anisotropic graphene-like photonic lattices

Understand

We study the scattering of waves off a potential step in deformed honeycomb lattices.

• For small deformations below a critical value, perfect Klein tunneling is obtained.
• This means that a potential step in any direction transmits waves at normal incidence with unit transmission probability, irrespective of the details of the potential.
• Beyond the critical deformation, a gap in the spectrum is formed, and a potential step in the deformation direction reflects all normal-incidence waves, exhibiting a dramatic transition form unit transmission to total reflection.