Nonmagnetic Transformation Optics for Two-Dimensional Optical Devices

In the past decade, some extraordinary devices, e.g., invisibility cloaks, perfect lenses and beam manipulators, have been realized thanks to a new design tool called transformation optics. This technique leads to unprecedented control of optical fields through complex material structures designed according to a predefined coordinate transformation. In order to achieve the intended flow of light without unwanted side-effects, transformation-optical devices must be impedance-matched. Often this leads to designs of sophisticated materials with inhomogeneous and anisotropic permeability and permittivity. In this contribution, we investigate how it is possible to relax the impedance-matching condition in realistic 2D transformation-optical systems.