TheHotSpring.com :: The tiny surface of the first effective ‘invisibility cloak’ allows light to bend around it in such a way that the optical density of an object underneath it is altered, generating the illusion of invisibility. There are ongoing efforts to build computerized overlays or built-in cladding that would allow even large vehicles like military tanks to appear invisible at a distance.
But the innovation inherent in this new cloaking device is vitally important. Instead of capturing images from one side of the object and transfering them to the other, where the viewer might see it, in order to give the illusion of invisibility, this new device would simply refract light, altering the apparent optical density of the object, and effectively ‘reshaping’ it into invisibility for the viewer on the other side.
According to InsideTech:
The journal Nature Materials reported on the development, which was constructed based on a carpet-like design theory first described by Professor John Pendry, from Imperial College London, in 2008. Teams involved in its current production included Michal Lipson and her team at Cornell University and Xiang Zhang, along with his team at University of California, Berkeley.
The cloaking device is described as “A silicon sheet measuring a few thousandths of a millimeter across and containing multiple miniature holes”, which permit the change in apparent “local density”. Prof. Zhang has also led two other teams of researchers who last year successfully “cloaked” 3D objects, using technology that allows the bending of light, but the new device is thought to be more sheer and efficient at doing so. The challenge will be to build a sample of the material large enough to test a full-scale 3D cloaking.
Also key to the project’s innovation is its use of silicon instead of metal for bending or manipulating light. Metals are dense, and therefore led to the “loss” of light, reducing their effectiveness for delivering the illusion of invisibility, whereas silicon absorbs comparatively little light, allowing for a more effective full-spectrum relay of light around the cloaked object.