The US army wants invisibility cloaks for its soldiers. Not just that - it has announced that it wants to test the best contenders within the next 18 months, Seems a bit unrealistic? Well, we may not be as far away as you think. In 2006, John Pendry, a theoretical physicist at Imperial College London, showed that it should be possible to bend light around an object and hide it using metamaterials - structures engineered at microscopic levels to channel electromagnetic waves. Since then, many devices trumpeted as invisibility cloaks have been described, but they only work in the lab with specific wavelengths or from certain angles, Now the US army has made a call for proposals from companies for wearable camouflage with a chameleon-like ability to change according to the background. So how will they manage this? Metamaterials are probably the best solution: previous efforts in this field using technology like LEDs were hampered by power and computing requirements.
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