Tunable metamaterials for conformally mapped Transformation Optics lenses

Abstract

The Transformation Optics (TO) design methodology allows for unprecedented control over wave behavior when coupled with advanced metamaterial technology [1,2]. The ubiquitous application of TO is the optical cloak of invisibility [1,2], but sub-wavelength hyperlenses and far-field collimating flat lenses [3–7] have also received a lot of attention due to their many possible practical applications. In addition, this class of TO devices tends to have a higher tolerance for dispersive, narrowband metamaterial properties. Most TO-derived devices require complicated material parameters for implementation [3–6], but choosing a conformal mapping as the transformation can greatly simplify the resulting material specifications [7]. It is shown here that a far-field collimating quadbeam lens derived from a conformal mapping can be implemented by a simple uniaxial homogeneous metamaterial. Full-wave simulations demonstrate the lens performance under excitation by a line current source. Moreover, a tunable metamaterial design for a TE-mode device is introduced along with simulation results showing the capability for beam scanning through electrical tuning of the metamaterial.