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Researchers in the US have made a “carpet cloak” that makes objects invisible to sound waves. The device is the first such cloak to work in air and could be used to improve the acoustics in concert halls or even to control unwanted noise.
The first light-based invisibility cloak was built in 2006 and the first for sound followed in 2010. Such cloaks are made from special man-made materials that are engineered to have optical or acoustic properties that vary throughout the device. As a result, incoming light or sound waves bend around the cloak and rejoin at the far side as if the cloak – and anything inside it – was never there.
In practice, however, it is extremely difficult to create materials with all the right properties and all cloaks built so far are extremely limited in how they work. The first sound cloak, for example, works in water not air and only works if the sound is propagating in 2D. Another important limitation of many cloaks is that they only work within a narrow band of frequencies.
Associate Creative Director at bloomfield knoble
Associate Creative Director at bloomfield knoble