Researchers are developing a new invisibility cloak that has multiple uses ranging from cloaking submarines for stealth operations all the way into the health industry, researchers say.
Along with the ability to bend sound waves around shaped cavities thanks to sonic metamaterial, it's possible to focus the sound waves into areas smaller than what regular ultrasound machines can handle: sub-millimeter-sized locations.
"Our focus is not about dampening noise, but to guide sound waves around structures," University of Illinois at Urbana Champaign professor Nicholas Fang told Discovery. "If we have a coating on a submarine that bends acoustics waves before they hit the surface, guiding them around the submarine smoothly, then you won't be able to detect a submarine using sonar."
It's possible that the same technology, instead of being used to cloak a submarine from sonar, may also be used to develop high-definition in-utero baby pictures or be used to detect tumors. The technology needs another three to five years before a "practical structure" can be developed for wide-scale testing.
Research and development into invisibility cloaks and similar technology is extremely popular at the moment, though this invisibility cloak is a bit different because of the size difference between electromagnetic waves and sound waves.
Traditional cloaking science, called "transformation optics," normally relies on metamaterials to redirect light. However, there have been great breakthroughs in a new "tapered optical waveguide" in development at Purdue University.
The ultrasonic metamaterial is much smaller than optical metamaterials with an ultrasonic metamaterial made of "tens or hundreds of microns," while an optical metamaterial is hundreds of nanometers.
The Discovery report describes the following:
The sonic invisibility cloak works a lot like a musical instrument.
Musical instruments amplify sound waves using shaped cavities. The sonic metamaterial uses cubes and octagons to create holes that can then bend the wave around the structure. The most obvious application would be as a coating for submarines that want to avoid detection from enemy sonar.
Other researchers have applauded the work done by UI researchers, and look forward to seeing how the technology develops. The actual technology for the metamaterials may not be overly difficult to manufacture, so it can be moved to real-world use much faster.