Harry Potter’s invisibility cloak edges closerMay 1st, 2009 - 12:27 pm ICT by ANI
London, May 1 (ANI): Scientists have made yet another advancement in bringing invisibility cloak closer to reality by developing a material that renders objects invisible to near-infrared light.
Previous “cloaks” had metals in their structure, which resulted in imperfect cloaking due to loss of light.
In the new study, researchers from New York’s Cornell University and the University of California at Berkeley have developed a carpet-based cloak using a dielectric - or insulating material - which absorbs far less light.
This “carpet” design was based on a theory first described by John Pendry, from Imperial College London, in 2008.
Michal Lipson and her team at Cornell University demonstrated a cloak based on the concept.
Xiang Zhang, professor of mechanical engineering at the University of California, Berkeley, led the other team.
“Essentially, we are transforming a straight line of light into a curved line around the cloak, so you don’t perceive any change in its pathway,” The BBC quoted Zang as saying.
The new material negates the distortion produced by the bulge of the object under it, bending light around it, and giving the illusion of a flattened surface.
According to Zhang, the cloak “changes the local density” of the object it is covering.
“When light passes from air into water it will be bent, because the optical density, or refraction index, of the glass is different to air.
“So by manipulating the optical density of an object, you can transform the light path from a straight line to to any path you want,” the expert said.
The new material does this via a series of minuscule holes - which are strategically “drilled” into a sheet of silicon.
“Where the holes are more dense, there is more air than silicon, so the optical density of the object is reduced,” Zhang said. (ANI)
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