Cloaking devices no longer belong to the realm of science fiction novels and television shows like Star Trek as Penn State University researchers have found the key to creating a cloaking device that can fully conceal all objects in its path.
The cloaking device in question is known as an acoustic ground cloak, and it works by taking sound waves underwater and completely redirecting them, as Phys.org report.
The device was created out of a very special metamaterial that causes sound waves to become bent in all directions near the object so that the object appears as though it simply is not there, as Amanda D. Hanford explained.
“These materials sound like a totally abstract concept, but the math is showing us that these properties are possible. So, we are working to open the floodgates to see what we can create with these materials.”
Researchers were able to see how well this idea works in reality by taking steel plates and arranging them in the shape of a three-foot pyramid beneath the water. They then used a hydrophone to create sound waves and found that the metamaterial they used was able to take these sound waves and completely redirect them elsewhere, making the steel plate pyramid completely invisible and acting as the perfect cloaking device.
— Phys.org (@physorg_com) May 10, 2018
Up until now, cloaking devices created out of such metamaterials have only been used to try and redirect sound waves occurring in the air rather than underwater. Hanford and researchers at Penn State University decided that testing out a cloaking device beneath water would be more desirable in terms of a major challenge as redirecting sound waves underwater is much more difficult due to the fact that air is less dense than water.
However, their attempt to mask the sound waves created by the hydrophone that were between 7,000 Hz and 12,000 Hz was a complete success. With a working device of this kind, objects underwater may be able to be completely hidden from sonar detection in the future.
The work involved with Penn State University’s new cloaking device will be discussed during the 175th Meeting of the Acoustical Society of America that is happening this week in Minneapolis.