How do cloaking devices work?

Answer 1

John Pendry's team suggest that by enveloping an object in a metamaterial cloak, light waves can be made to flow around the object in the same way that water would do so. Professor Pendry explained:"Water behaves a little differently to light. If you put a pencil in water that's moving, the water naturally flows around the pencil. When it gets to the other side, the water closes up, a little way downstream, you'd never know that you'd put a pencil in the water - it's flowing smoothly again. Light doesn't do that of course, it hits the pencil and scatters. So you want to put a coating around the pencil that allows light to flow around it like water, in a nice, curved way.¨ So in effect what it would have to do is to hold on to the light waves allowing it to reassemble itself once it has passed the cloak.