Metamaterials hold the elusive promise of the true invisibility cloak, one that bends light right around objects to make them invisible to viewers. But most metamaterials with any kind of potential can only be fabricated in very small sizes, and even the ones that work well--and there are a few--generally don't work in the visible spectrum.
The search for the perfect invisibility cloak lumbers onward, but that lumbering is starting to pick up speed. We're hearing more and more these days about metamaterials, the possibilities of time cloaking, and other such future-stuff.
We’ve written previously about the theoretical possibility of “event cloaks”--metamaterial space-time devices that could theoretically conceal an entire event in time from the view of an outsider. Well, while some bright minds were just talking about bending space-time to their whims, a team at Cornell was doing it. And it works. For 110 nanoseconds.
A new acoustic invisibility cloak made of a plastic metamaterial makes objects invisible to sound waves, researchers say. It could be used to shield ships from sonar, or build better soundproof walls for concert halls and other spaces. We’ve seen this idea before, but now Duke University researchers have actually built it.
Today's stealth fighters, such as the F-22 Raptor, may do pretty well in concealing their radar signature, but mathematicians say that a new active cloaking technique could someday generate electromagnetic fields to hide submarines from sonar, or even protect buildings from earthquakes.
Disaster film director Roland Emmerich must be quaking in his boots knowing that his movies may soon have to be a little less destructive. With the invention of an "invisibility cloak" for buildings, earthquake damage could be significantly minimized. Using a series of concentric rings in the foundation of a building, this "cloak" directs seismic waves around a building, rather than destructively against and through it.