Tailo­red distri­bu­ti­ons of artifi­cial materi­als called metama­te­ri­als allow for desig­ning and fabri­ca­ting invisi­bi­lity cloaks in optics and counter­parts thereof in other areas of physics. For example, cloaking can be used for making metal contact grids on solar cells invisi­ble, thereby incre­asing the energy conver­sion effici­ency by as much as 10% [1]. In the diffu­sive regime of light propa­ga­tion, invisi­bi­lity cloaking is also possi­ble [2] and can, for example, be applied for homoge­ni­zing the light emission from large-area organic light-emitting diodes (OLED). The latter were inspi­red by thermal cloaks [3].

In a project of the Hector Fellow Academy jointly conduc­ted with Hector Fellow Peter Gumbsch, mecha­ni­cal metama­te­ri­als are being inves­ti­ga­ted. This has led to static mecha­ni­cal cloaks [4,5] and to modified penta­mode metama­te­ri­als [6] that might enable cloaks for mecha­ni­cal waves in the future. Further­more, tailo­red buckling nonlinear mecha­ni­cal metama­te­ri­als can be designed that allow for large speci­fic energy absorp­tion – while being reusable. Metama­te­ri­als with tailo­red thermal expan­sion are another area of current research.

As another example for optical metama­te­rial, three-dimen­sio­nal gold-helix archi­tec­tures can be used as broad­band circu­lar polari­zers [7]. Advan­ced versi­ons thereof [8] take advan­tage of stimu­la­ted emission deple­tion (STED) laser litho­gra­phy beyond the Abbe diffrac­tion limit [9].

A more complete list of publi­ca­ti­ons of the Wegener group can be found at http://www.aph.kit.edu/wegener/77.php