One-way propagation of light in Born-Infeld-like metamaterials
  We propose and investigate a family of nonlinear metamaterials in which light rays propagate just in one direction -- one-way propagation. Furthermore, we argue how such nonlinear media could provide an analog model for investigating the Born-Infeld Lagrangian in the realm of fields larger than its scale field. 
Vitorio A. De Lorenci, Jonas P. Pereira
physics.optics hep-th