Designing wave vector manipulation devices using a transformation optics   approach
  A transformation optics approach was used to derive a general method for designing electromagnetic devices able to manipulate the wave vectors in the specific manner required by the functionality of the device. While the wave paths inside the device remain of a secondary importance the wave vectors are gradually changed in the desired way by choosing the appropriate coordinate transformation. The proposed method was applied to design both converging and diverging flat lenses. Computer simulations revealed the focusing ability of a converging flat lens designed using the proposed technique. 
Mircea Giloan
physics.optics