Angular-dependent Klein tunneling in photonic graphene

Abstract

The Klein paradox consists in the perfect tunneling of relativistic particles through high potential barriers. As a curious feature of particle physics, it is responsible for the exceptional conductive properties of graphene. It was recently studied in the context of atomic condensates and topological photonics and phononics. While in theory the perfect tunneling holds only for normal incidence, so far the angular dependence of the Klein tunneling and its strong variation with the barrier height were not measured experimentally. In this work, we capitalize on the versatility of atomic vapor cells with paraxial beam propagation and index patterning by electromagnetically-induced transparency. We report the first experimental observation of perfect Klein transmission in a 2D photonic system (photonic graphene) at normal incidence and measure the angular dependence. Counter-intuitively, but in agreement with the Dirac equation, we observe that the decay of the Klein transmission versus angle is suppressed by increasing the barrier height, a key result for the conductivity of graphene and its analogues.

References in corpus (8)

• Chiral tunneling and the Klein paradox in graphene
• Topological Photonics
• Scheme to Achieve Silicon Topological Photonics
• Evidence of Klein tunneling in graphene p-n junctions
• Transport measurements across a tunable potential barrier in graphene
• Creating and Steering Highly Directional Electron Beams in Graphene
• Confining stationary light: Dirac dynamics and Klein tunneling
• Symmetry breaking and (pseudo)spin polarization in Veselago lenses for massless Dirac fermions

Cited by in corpus (8)

• Loss-difference-induced localization in a non-Hermitian honeycomb photonic lattice
• Electronic properties of two-dimensional rectangular graphyne based on phenyl-like building blocks
• Encoding quantum bits in bound electronic states of a graphene nanotorus
• Paraxial fluids of light
• Optical Snake States in Photonic Graphene
• Klein Tunneling of Gigahertz Elastic Waves in Nanoelectromechanical Metamaterials
• Perfect transmission of a Dirac particle in one-dimension double square barrier
• Skew scattering and ratchet effect in photonic graphene