Quasi-conformal transformation optics techniques for gradient index devices on graphene

We present the use of quasi-conformal transformation optics techniques to design planar devices on graphene sheets. First, we discuss the pertinent design equations for linking permittivity tensors to the electronic transport properties of graphene. We then demonstrate the process by designing a planar quad-beam collimator on graphene. The required gradients for transformation optics devices are then realized by controlling the graphene´s substrate parameters.