Engineers devise invisibility shield

Andrea Alù and Nader Engheta of the University of Pennsylvania believe that a "plasmonic cover" could render objects nearly invisible.

We see objects because light bounces off them; if this scattering of light could be prevented, they would become invisible. The plasmonic screen suppresses scattering by resonating in tune with the illuminating light.

But the concept as it stands would have to be tuned to suit each different object it hides. Besides, a particular shield only works for one specific wavelength of light.

Furthermore, the wavelength of the light being scattered must have roughly the same size as the object. So shielding from visible light would be possible only for microscopic objects; larger ones could be hidden only to long-wavelength radiation such as microwaves. The technology cannot be used to hide people or vehicles from human vision.

However, the effect could be useful for making antiglare materials, for concealing large objects such as spaceships from sensors or telescopes that used long-wavelength radiation instead of visible light.

Types of invisibility shielding have been developed before, but these mostly use the chameleon principle. Ray Alden has proposed a system that project a replica of the scene appearing behind an object from its front surface. Researchers in Tokyo are working on a camouflage fabric that uses a similar principle.

Via Nature.