27-09-11 Now,an invisibility cloak you can see

The first invisibility cloaks that live up to their whimsical nickname have arrived.Unlike previous cloaks,which manipulated specially polarized light or microwaves and infrared already invisible to humans,two new approaches bend ordinarily visible light.Disguised by one of these materials,an object could vanish before your eyes.If invisibility is the goal,eventually you need to build something thats detectable by the human eye,says Majid Gharghi,an applied physicist at the University of California,Berkeley.The new carpet cloak made by Gharghis team team is a sheet of silicon nitride draped over a bump.Usually,light striking this bulge would scatter,revealing the anomaly.But thousands of tiny holes of different sizes etched into the silicon nitride guide the light,hiding the bump and anything concealed beneath it.Light over a wide range of colors behaves as if striking a flat surface instead,the researchers report in the July 13 Nano Letters.The experimental demonstration at blue,green and red light looks impressive,says Steven Cummer,an electrical engineer at Duke University.