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