Invisibility cloaking without superluminal propagation
  Conventional cloaking based on Euclidean transformation optics requires that the speed of light should tend to infinity on the inner surface of the cloak. Non-Euclidean cloaking still needed media with superluminal propagation. Here we show by giving an example that this is no longer necessary. 
Janos Perczel, Tomas Tyc, Ulf Leonhardt
physics.optics