His group also published a paper on negative refraction in the visible in a 2D metallic nanowire array in <a target="_blank" href="http://www.sciencemag.org/content/321/5891/930" class="externerlink">SCIENCE</a>. Der <a target="_blank" href="http://www.spiegel.de/wissenschaft/mensch/0,1518,571234,00.html" class="externerlink">SPIEGEL</a> reported on their discovery.