Comprehensive conclusions

John Pedry commented: "There's a rule in the internal structure of a metamaterial: it has to be smaller than the wavelength of the radiation. For radar, it's three centimeters. You can easily design something a few millimeters in size. When you enter optical radiation—visible light—the wavelength is less than a micron. So your microstructure has to be several dozen nanometers in size. We're just now learning how to create nanotechnology... maybe we could do it in five or ten years, but certainly not today."

Researchers say that if an object can be hidden from microwaves, it can also be hidden from radar – a possibility that will attract military interest. Professor Pendry said the metamaterial cloak could be created to wrap around a military aircraft or tank. However, he added: "You can't expect the cloak to be too thin. Contrary to the hype surrounding Harry Potter, it's not something that flaps in the wind; it's something like a hangar."

The cloak could hide objects from terahertz waves, the regime used in numerous detection technologies, or even from cell phone and magnetic field frequencies.