Klein tunneling in driven-dissipative photonic graphene

We theoretically investigate Klein tunneling processes in photonic artificial graphene. Klein tunneling is a phenomenon in which a particle with Dirac dispersion going through a potential step shows a characteristic angle- and energy-dependent transmission. We consider a generic photonic system consisting of a honeycomb-shaped array of sites with losses, illuminated by coherent monochromatic light. We show how the transmission and reflection coefficients can be obtained from the steady-state field profile of the driven-dissipative system. Despite the presence of photonic losses, we recover the main scattering features predicted by the general theory of Klein tunneling. Signatures of negative refraction and the orientation dependence of the intervalley scattering are also highlighted. Our results will stimulate the experimental study of intricate transport phenomena using driven-dissipative photonic simulators.