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March 02, 2005
A theoretical invisibility device...
This article says that two scientists Mr. Alù and Mr. Engheta of the University of Pennsylvania have come up with a theoretical method of making an object invisible. ---
- The key to the concept is to reduce light scattering. We see objects because light bounces off them; if this scattering of light could be prevented (and if the objects didn't absorb any light) they would become invisible. Alù and Engheta's plasmonic screen suppresses scattering by resonating in tune with the illuminating light.
Plasmons are waves of electron density, caused when the electrons on the surface of a metallic material move in rhythm. The researchers say that a shell of plasmonic material will scatter light negligibly if the light's frequency is close to the resonant frequency of the plasmons. The scattering from the shell effectively cancels out the scattering from the object.
OK, the current problems: 1) They haven't made this yet. 2) It only works on a narrow band of light (such as invisible to green light but visible on red light) 3) only tiny objects can be hidden from visible light through this method.
Still, what was once only a theory can sometimes become very powerful reality (like lasers).
Posted by rakhier at March 2, 2005 12:06 PM