Image courtesy of L. Sanchis and others, Physics Review Letters, 2013.
Fig. 1 a) Schematic representation of the 3D designed cloak. (b) Photograph of the cloak taken after its fabrication. The total length of the sample along the z axis is 17 cm. (c),(d) Photographs taken inside the anechoic [echo-less] room.
Cloaking devices—they’re not just for creepy Klingon warships any more!
This is Sandra Tsing Loh with the Loh Down on Science
Saying, at least in water. Sonar detects otherwise elusive undersea objects. How? By sending out a sound and listening for the echo bouncing off the object.
But now a Spanish engineer has developed the world's first 3D acoustic cloak. It looks like five dozen puny, multi-sized donuts, stacked in the shape of an egg. The object to be hidden goes inside.
The bizarre structure is what gives the cloak its elusive power. Usually, when sound waves hit something, they reflect and scatter. So they can be detected.
But when sound waves hit an object inside the acoustic cloak? They scatter off the object and off the cloak. The cloak's rings shuffle the waves. So they collide and cancel each other out!
Currently, the cloak only hides things smaller than two inches, but the engineer wants to scale up to submarine size.
Until then, it could be the basis for an exciting if very tiny Sean Connery movie. We’d watch!
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