‘Invisible’ Material Can Now Fool Your Eyes

By Noah Shachtman November 4, 2010
4:40 pm
Categories: Science!





Don’t start picking out the pattern of your cloak, yet. But invisibility just became a whole lot more likely.



Tech journalists and military dreamers have talked about real-life invisibility cloaks for a while, and with good reason. With their specialized structures, so-called “metamaterials” can bend light around objects, making ‘em disappear.



But you haven’t seen the likes of Harry Potter or Frodo Baggins training at Fort Bragg (Fodo Braggins, maybe?), because the trick doesn’t work with visible light. Metamaterials warp things like infrared light or terahertz waves, neither of which we can see in the first place. In other words, we could still make out the “invisible” object with our own two eyes.



Or at least, that used to be the case. Physicists at the University of St. Andrews appear to have made a breakthrough, however. They’ve created a metamaterial that really does work in the “optical range,” the scientists note in the New Journal of Physics.



Not only did Andrea Di Falco and his research partners put together a metamaterial that could bend visible light. They built it in a way that could lead to larger-scale manufacturing — and real-world applications. Not just cloaks, but lenses made out of metamaterials that can zoom to the micron level, making it possible to spot germs, chemical agents and even DNA, using basically a pair of binoculars.





“It clearly isn’t an invisibility cloak yet — but it’s the right step toward that,” Ortwin Hess, a physicist at Imperial College London, tells the BBC. “A huge step forward in very many ways.”



Typically, metamaterials are built on top of rigid, brittle substrates like silicon. But that limits their size, and the wavelengths at which they work. Di Falco’s group instead made materials out of a superthin layer of flexible polymer, since “a ‘real’ cloaking device would have to be deformable and extend over a large area,” they write. If Di Falco and his partners can stack enough of these materials together — and show they can work while folded — we could be on our way to Hogwarts.