Navigation Links
Not only invisible, but also inaudible
Date:12/20/2011

This press release is available in German.

Progress of metamaterials in nanotechnologies has made the invisibility cloak, a subject of mythology and science fiction, become reality: Light waves can be guided around an object to be hidden, in such a way that this object appears to be non-existent. This concept applied to electromagnetic light waves may also be transferred to other types of waves, such as sound waves. Researchers from Karlsruhe Institute of Technology (KIT) have now succeeded in demonstrating for the first time an invisibility cloak for elastic waves. Such waves also occur in strings of a guitar or drum membranes.

It is as if Harry Potter had a cloak that also makes him unhearable. "Maybe a place of peace and quiet in the Christmas season," say the KIT researchers, who succeeded in transferring the concepts underlying the optical invisibility cloak to acoustic waves in a plate.

"The key to controlling waves is to specifically influence their local speed as a function of the 'running direction' of the wave," says Dr. Nicolas Stenger from the Institute of Applied Physics (AP). In his experiment, he used a smartly microstructured material composed of two polymers: A soft and a hard plastic in a thin plate. The vibrations of this plate are in the range of acoustic frequencies, that is some 100 Hz, and can be observed directly from above. The scientists found that the sound waves are guided around a circular area in the millimeter-thin plate in such a way that vibrations can neither enter nor leave this area. "Contrary to other known noise protection measures, the sound waves are neither absorbed nor reflected," says Professor Martin Wegener from the Institute of Applied Physics and coordinator of the DFG Center for Functional Nanostructures (CFN) at KIT. "It is as if nothing was there." Both physicists and Professor Martin Wilhelm from the KIT Institute for Chemical Technology and Polymer Chemistry have now published their results in the journal "Physical Review Letters."

The scientists explain their idea by the following story: A city, in the shape of a circle, suffers from noisy car traffic through its center. Finally, the mayor has the idea to introduce a speed limit for cars that drive directly towards the city: The closer the cars come to the city area, the slower they have to drive. At the same time, the mayor orders to build circular roads around the city, on which the cars are allowed to drive at higher speeds. The cars can approach the city, drive around it, and leave it in the same direction in the end. The time required corresponds to the time needed without the city. From outside, it appears as if the city was not there.


'/>"/>
Contact: Monika Landgraf
presse@kit.edu
49-721-608-47414
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. The inaudible symphony analyzed
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/22/2016)... On Monday, the Department of Homeland Security ... solutions for the Biometric Exit Program. The Request for ... (CBP), explains that CBP intends to add biometrics to ... United States , in order to deter visa ... Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
(Date:6/16/2016)... FRANCISCO , June 16, 2016 ... size is expected to reach USD 1.83 ... by Grand View Research, Inc. Technological proliferation and ... banking applications are expected to drive the market ... ) , The development of advanced ...
(Date:6/9/2016)... TURKU, Finland , June 9, 2016 ... French National Police deploy Teleste,s video security solution to ensure ... France during the major tournament ... and data communications systems and services, announced today that its ... Police Prefecture to back up public safety across ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... ... (Yeast and Mold) microbial test has received AOAC Research Institute approval 061601. , ... tests introduced last year,” stated Bob Salter, Vice President of Regulatory and Industrial ...
(Date:6/23/2016)...   EpiBiome , a precision microbiome engineering company, ... financing from Silicon Valley Bank (SVB). The financing will ... its drug development efforts, as well as purchase additional ... has been an incredible strategic partner to us – ... would provide," said Dr. Aeron Tynes Hammack , ...
(Date:6/23/2016)... ... 23, 2016 , ... In a new case report published today in STEM ... who developed lymphedema after being treated for breast cancer benefitted from an injection of ... dealing with this debilitating, frequent side effect of cancer treatment. , Lymphedema ...
(Date:6/23/2016)... -- Andrew D Zelenetz , ... Published recently in Oncology & ... Andrew D Zelenetz , discusses the fact ... placing an increasing burden on healthcare systems worldwide, ... the patents on many biologics expiring, interest in ...
Breaking Biology Technology: