A Three-Dimensional Object Sound Cloaked For The First Time

By Nick Venable | 8 years ago

Cloak

Sonar detection has made for some of the most tense scenes in submarine film history, along with actually having real-life applications like finding enemy submarines. And possibly something about a professional league of Marco Polo players, but that may have been a cold-medicine hallucination. Cloaking three-dimensional objects from sonar has been mostly impossible thus far, due to the way sound waves scatter after hitting an object. Now that has changed.

Current techniques of eliminating wave scatter aim involve steering sound around objects, but electrical engineer José Sánchez-Dehesa and colleagues from Spain’s Polytechnical Institute of Velencia went a different route and built a cloak that would cause the scattered waves to cancel each other out. Surely this new approach would be more expensive and time-consuming, right? Not at all. Instead of the expensive lab-produced materials that nature never dreamed of, a system of rings created by a 3D printer were used to encapsulate the cloaked object, in this case an eight-centimeter plastic sphere. It looks like the spaceship for an alien species obsessed with barrels, or possibly the coolest beer can ever.

The researchers used a computer algorithm to design the structure, created from 60 of the plastic rings, and simulated scattered sound waves within the device getting in each other’s way and rending themselves moot. Or mute, as it were. It’s noted that noise-cancelling headphones do something similar by emitting sound waves that cancel out a room’s ambient din.

The downside of this great news is that it was tested in an extremely specific way, and it won’t be used on the large scale for quite a while. The team hung their invention in an echo-free chamber and blasted a bunch of different sound waves at it. For most frequencies, the sound scattered by the sphere inside was easily detectable,  but once the pitch reached 8.55 kilohertz, the sensors behind the device were no longer able to detect the sphere inside. History made.

Because this is an amazing advancement in the way we understand a portion of science, I’ll give you two guesses as to which kind of gigantic organization was partially responsible for it. The U.S. Office of Naval Research. Because if it can’t be militarized, what’s the fucking point?

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