It may look like the love child between a Japanese pagoda and a Mayan pyramid, but this pile of punctured plastic is actually a cloaking device. No, it doesn't disappear, taking its contents with it. It's not that sort of cloaking device. What this plastic pagoda actually does is hide from sound waves.
While that may seem less impressive than a visual cloaking device, it's pretty darn awesome, nonetheless. No matter what direction sound waves are fired at the cloak, they pass right through as if nothing were there at all. That means that anything navigating by sonar, be it a nuclear submarine or a fruit bat, has absolutely no idea that this thing exists. Moreover, anything inside the pyramid is made undetectable as well.
As the Duke University team that developed the cloak quickly discovered, sound waves are actually pretty hard to fool. Making it seem as if a sound wave has passed through an object and reflected off a surface further away, you actually have to slow the sound wave down without dissipating it or altering its frequency. It's a bit like jumping into a car's back seat as it passes you at 60 miles per hour.
Not surprisingly, both the Army and Navy had a hand in funding the project, but sonar avoidance might not be its only application. Future concert ahlls could benefit tremendously, leaving the very idea of acoustic dead zones in the past.
Via Duke University