Plasmonic Screen

Objects are seen because of the light that scatters from it. Invisibility can occur only if no light was scattered or absorbed by the object -- if light is absorbed, the energy would raise the temperature of the object, making it radiate. Researchers have theoretically discovered a way of making things invisible by employing plasmons. Plasmons are waves of electron density resulting from electrons on the surface of a metallic object moving in rhythm. If a screen made of plasmons that resonated at the same frequency of an illuminating light was used to shield an object, the screen would reduce the scattering of light, making the screen and object near invisible.

Are we going to get invisibility cloaks anytime soon? Well, not quite. There are a few problems, the major ones being that, 1) a plasmonic screen would only be effective against one wavelength of light; and, 2) an object being shielded would have to be roughly the same size as the wavelength being shielded from -- so large objects would only be invisible from microwaves. Still, it is an interesting concept that may find applications. (You can read the journal article here. [PDF])