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Real-world Sci-fi: Invisibility Cloaks

By Chelsea Hedquist, HowStuffWorks.com

Not Just a Farfetched Fantasy

The power of invisibility comes in all kinds of flavors in the world of science fiction and fantasy, from Bilbo Baggins' magical ring to Invisible Woman's superhuman powers (thanks to an unhealthy dose of cosmic radiation). No matter the method, the ability to disappear from sight always seems very useful — and downright awesome. Perhaps Harry Potter has it easiest with his handy invisibility cloak, which plays a vital role in many of his escapades. While a cloak of invisibility may seem no less far-fetched than superpowers or magical rings, new technology makes it plausible to imagine invisibility that goes beyond sci-fi and fantasy.

The Science of Real-world Invisibility

So far science has produced two types of technology to create real-world invisibility cloaks. The first, optical camouflage, uses augmented reality technology and operates more on the principle of creating the illusion of invisibility, rather than actually making an object or person disappear. It accomplishes this feat using a whole slew of equipment: a digital video camera, a reflective garment, a computer, a projector, and a special mirror called a combiner. Compared to Harry Potter's cloak — which he regularly shoves in a backpack to use in a pinch — all this gear sounds quite cumbersome. Moreover, this type of invisibility only works in two dimensions.

The second invisibility technology comes closer to replicating J.K. Rowling's imagined cloak. Scientists use metamaterials — composed of artificial matter and created using nanotechnology — to form a fabric (though really more like a solid structure) that can actually make an object invisible to the human eye. The metamaterial fabrics achieve this by bending or diverting light waves around objects. Since our eyes actually only process light and how it intercepts objects in our world, diverting light around objects can make them literally disappear from our vision.

VIDEO: PopSci's Future Of: Invisibility Cloak