The Dream of Invisibility
The cloaking device is fiberglass and copper metamaterial that measures 13 centimeters by one centimeter. Metamaterial essentially gains its electromagnetic properties from its configuration rather than its composition. Currently metamaterials are limited in size by the radiation waves that associate with them, but physicists and engineers continually work toward expanding the breadth and depth of the range for broader functionality. The cloak unveiled at Duke University this week successfully hid a copper cylinder from electromagnetic waves, rendering it virtually invisible. To see a demonstration, go to youtube.com.
David Schurig, a physicist at Duke, described the process like this: "You can think of it visually as like water flowing around a rock smoothly. If you look downstream from the rock, the stream has been restored to its original flow pattern, and you can't tell that the water flowed around a rock by looking at the water." The cloak doesn't hide light, but incorporating that feature is one of the next challenges scientists face in advancing the technology. But even the technology as it stands now, blocking electromagnetic detection, has a wide range of potential uses, not least military applications. Current stealth technology allows planes and other devices to avoid most radar recognition, but it's not flawless. Equipping items with a cloaking device that avoids electromagnetic discovery would make them completely undetectable except by sight.
Another related article came to my attention this week. It covers invisibility as part of a larger exhibition on science running this fall at the Royal Academy of Science in London. This technique of rendering objects invisible involves nanotechnology and tackles the visibility of light on a molecular level. It doesn't use metamaterial, but rather quantum physics principles applied in a controlled lab environment warp the energy waves of electrons so that they neutralize to the point of allowing light to pass through unobstructed. The object then appears transparent to the observer.
Only a minute or two of thought is needed for us to think of multiple possible uses, both good and bad, for this kind of technology. Do we want to live in a world that incorporates and factors invisibility? I don't know the answer, and as with all cutting-edge science we will tread thrilling and frightening ethical lines. Regardless, the technology is there, and maybe someday we'll be able to buy our own cloaking device on eBay. One can only dream.