Metamaterials are already being used to create invisibility cloaks and “temporal cloaks,” but now engineers from Duke University have turned metamaterials to the task of creating a 3D acoustic cloak. In the same way that invisibility cloaks use metamaterials to reroute light around an object, the acoustic cloaking device interacts with sound waves to make it appear as if the device and anything hidden beneath it isn’t there.
Steven Cummer, professor of electrical and computer engineering, and his colleagues at Duke University constructed their acoustic cloak using several sheets of plastic plates dotted with repeating patterns of holes. The plastic sheets, which were created using a 3D printer, were stacked on top of each other to form a device that resembles a pyramid in shape. The geometry of the sheets and the placement of the holes interact with sound waves to make it appear as if the device and anything sitting underneath it isn’t there.
via Gizmag
