Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TECH SPACE
Lego-like wall produces acoustic holograms
by Staff Writers
Durham NC (SPX) Oct 18, 2016


This is a close up look at the metamaterial device that can create acoustic holograms. Each grid or block contains a spiral of one of 12 various densities, each of which slows sound waves by a different amount. Image courtesy Steve Cummer, Duke University. For a larger version of this image please go here.

Research Triangle engineers have developed a simple, energy-efficient way to create three-dimensional acoustic holograms. The technique could revolutionize applications ranging from home stereo systems to medical ultrasound devices.

Most everyone is familiar with the concept of visual holograms, which manipulate light to make it appear as though a 3-D object is sitting in empty space. These optical tricks work by shaping the electromagnetic field so that it mimics light bouncing off an actual object.

Sound also travels in waves. But rather than electromagnetic energy traveling through space, sound propagates as pressure waves that momentarily compress the molecules they are traveling through. And just like visible light, these waves can be manipulated into three-dimensional patterns.

"We show the exact same control over a sound wave as people have previously achieved with light waves," said Steve Cummer, professor of electrical and computer engineering at Duke University. "It's like an acoustic virtual reality display. It gives you a more realistic sense of the spatial pattern of the sound field."

In a paper published Oct. 14 in Nature Scientific Reports, researchers at Duke and North Carolina State University show that they can create any three-dimensional pattern they want with sound waves. The achievement is made possible by metamaterials - synthetic materials composed of many individual, engineered cells that together produce unnatural properties.

In this case, the metamaterials resemble a wall of Legos. Each individual block is made of plastic by a 3-D printer and contains a spiral within. The tightness of the spiral affects the way sound travels through it - the tighter the coil, the slower sound waves travel through it.

While the individual blocks can't influence the sound wave's direction, the entire device effectively can. For example, if one side of the sound wave is slowed down but not the other, the resulting wave fronts will be redirected so that the sound is bent toward the slow side.

"Anybody can tell the difference between a single stereo speaker and a live string quartet playing music behind them," explained Yangbo "Abel" Xie, a doctoral student in Cummer's laboratory. "Part of the reason why is that the sound waves carry spatial information as well as notes and volume."

By calculating how 12 different types of acoustic metamaterial building blocks will affect the sound wave, researchers can arrange them in a wall to form any wave pattern on the other side that they want. With enough care, the sound waves can produce a specific hologram at a specific distance away.

"It's basically like putting a mask in front of a speaker," said Cummer. "It makes it seem like the sound is coming from a more complicated source than it is."

Cummer and Xie, in collaboration with Yun Jing, assistant professor of mechanical and aerospace engineering at NC State, and Tarry Shen, a doctoral student in Jing's lab, proved their sound mask works in two different ways. In the first test, they assembled a metamaterial wall that manipulated an incoming sound wave into a shape like the letter "A" about a foot away. In a second demonstration, they showed that the technique can focus sound waves into several "hot spots" - or loud spots - of sound, also a foot from the device.

There are existing technologies that can also produce this effect. Modern ultrasound imaging devices, for example, use phased arrays with many individual transducers that can each produce precisely controlled sound waves. But this approach has its drawbacks.

"If you've ever had an ultrasound done, you know there's a small wand attached to a much bigger machine a few feet away," said Cummer. "Not only can this setup be cumbersome, it consumes an enormous amount of power. Our approach can help produce the same effect in a cheaper, smaller system."

For the metamaterial device to work in such applications, however, each cell must be smaller than the waves it is manipulating. And for ultrasound technologies that operate in the megahertz range, this means the individual cells would have to be 100 times smaller than in the current demonstration blocks.

Cummer and Xie are looking for industry partners to show that this sort of fabrication would be possible. They are also shopping the idea around to industries that work in the kilohertz range, such as aerial sensing and imaging technologies. And of course, they're speaking with sound companies to make a single speaker sound more like a live orchestra.

"We're currently in the exploration phase, trying to determine where this technology would be useful," said Xie. "Any scenario where your goal is to control sound, this idea could be deployed. And it could be deployed to make something totally new, or to make something that already exists better, simpler or cheaper."

Research paper: "Acoustic Holographic Rendering with Two-Dimensional Metamaterial-Based Passive Phased Array," Yangbo Xie, Chen Shen, Wenqi Wang, Junfei Li, Dingjie Suo, Bogdan-Ioan Popa, Yun Jing, and Steven A. Cummer. Nature Scientific Reports, Oct. 14, 2016. DOI: 10.1038/srep35437


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Duke University
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
TECH SPACE
Solving a cryptic puzzle with a little help from a hologram
Ramat Ganl Israel (SPX) Oct 10, 2016
A recent discovery published in Nature Physics provides an innovative technique for calculating the shapes of electrons. This finding will help scientists gain a better and faster understanding of the properties of complex materials. Dr. Emanuele Dalla Torre, from Bar-Ilan University, together with Dr. Yang He and Prof. Eugene Demler, from Harvard University, used holographic logic to comp ... read more


TECH SPACE
Spectacular Lunar Grazing Occultation of Bright Star on Oct. 18

Hunter's Supermoon to light up Saturday night sky

Small Impacts Are Reworking Lunar Soil Faster Than Scientists Thought

A facelift for the Moon every 81,000 years

TECH SPACE
Euro-Russian craft enters Mars orbit, but lander's fate unknown

Anxious wait for news of Mars lander's fate

What! - Go To Mars?

Modeling floods that formed canyons on Earth and Mars

TECH SPACE
Beaches, skiing and tai chi: Club Med, Chinese style

NASA begins tests to qualify Orion parachutes for mission with crew

New Zealand government open-minded on space collaboration

Growing Interest: Students Plant Seeds to Help NASA Farm in Space

TECH SPACE
Chinese astronauts reach orbiting lab: Xinhua

Astronauts enjoy range of delicacies on Shenzhou XI

China to enhance space capabilities with launch of Shenzhou-11

China launches 2 astronauts for 33-day mission

TECH SPACE
Two Russians, one American blast off to ISS

Tools Drive NASA's TReK to New Discoveries

Hurricane Nicole delays next US cargo mission to space

Automating sample testing thanks to space

TECH SPACE
Swedish Space Corporation Celebrates 50th Anniversary of Esrange Space Center

US-Russia Standoff Leaves NASA Without Manned Launch Capabilities

Ariane 5 ready for first Galileo payload

ILS Announces Two Missions under Its EUTELSAT Multi-Launch Agreement

TECH SPACE
Proxima Centauri might be more sunlike than we thought

Stars with Three Planet-Forming Discs of Gas

TESS will provide exoplanet targets for years to come

The death of a planet nursery?

TECH SPACE
Lego-like wall produces acoustic holograms

U.S. State Dept. approves $194 million radar sale to Kuwait

Pushing the boundaries of magnet design

Polymer breakthrough to improve things we use everyday




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement