Wednesday, October 5, 2011

‘Invisibility Cloak’ Uses Mirages to Make Objects Vanish

Once again Science Fiction becomes reality.



Wired
It happens when a big change in temperature over a small distance bends light rays so they’re sent towards the eye rather than bouncing off the surface. So if you see a pool of blue water in the middle of the desert it’s just the blue sky being redirected from the warm ground and sent directly into your eye. Your brain, being the clever little computer that it is, swaps this mad image out for something more sensible: a pool of water.

With that in mind, the researchers wanted to find a material that has an exceptional ability to conduct heat and quickly transfer it to surrounding areas to mimic the light-distorting temperature gradients of the desert. That material, they found, was sheets of carbon nanotubes.

The nanotubes — one-molecule-thick sheets of carbon wrapped up into cylindrical tube — have the density of air but the strength of steel. They’re also excellent conductors, making them an ideal material to exploit the “mirage effect.”


Through electrical stimulation, the transparent sheet of highly aligned nanotubes can be quickly heated to high temperatures. By transferring that heat to its surrounding areas, a steep temperature gradient is generated, which causes the light rays to bend away from the object concealed behind the device. Therefore, the object appears invisible.

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