Curved trajectories on transformed metal surfaces: Luneburg lens,   beam-splitter, invisibility carpet and black hole for surface plasmon   polaritons
  Transformational optics are shown to markedly enhance the control of the electromagnetic wave trajectories within metamaterials with unconventional functionalities such as a beam splitter, a toroidal carpet, a Luneburg lens and a black hole, all of which are specially designed for surface plasmon polaritons propagating on a metal plate 
Kadic Muamer, Dupont Guillaume, Tieh-Ming Chang, Sebastien Guenneau,   Stefan Enoch
physics.optics physics.soc-ph