Duke University has built the first 3D omnidirectional acoustic invisibility cloak. The cloaking device, which takes the form of a pyramid of perforated plastic, is hidden from sound waves striking it from any direction — if you fired some sound waves at the device, using sonar for example, you would see nothing; not the cloak, and not the object beneath it. This has obvious applications in the military, but also in architectural acoustics. Here at ExtremeTech we’ve written a lot about metamaterials — specially fabricated materials that have properties never found in nature — and how they allow for the creation of some seriously outlandish devices, such as invisibility cloaks and superlenses. Metamaterials aren’t necessarily restricted to bending light waves in odd ways, though; they can also be used to manipulate acoustic waves, too. Read More at ExtremeTech.
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