Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Beyond good vibrations: New insights into metamaterial magic

07.11.2017

Metamaterials offer the very real possibility that our most far-fetched fancies could one day become real as rocks. From invisibility cloaks and perfect lenses to immensely powerful batteries, their super-power applications tantalize the imagination. That said, so far "tantalize" has been the operative word, even though scientists have been studying metamaterials for more than 15 years.

"Not many real metamaterial devices have been developed," says Elena Semouchkina, an associate professor of electrical engineering at Michigan Technological University. Soldiers can't throw invisibility cloaks over their shoulders to elude sniper fire, and no perfect lens app lets you see viruses with your smartphone. In part, that's because traditionally, researchers overly simplify how metamaterials actually work. Semouchkina says their complications often have been ignored.


The shape and positioning of the rods in this metamaterial cause light--the arrow--to bend at a negative angle, a process called negative refraction. Better understanding of this dynamic will speed the development of new metamaterials such as perfect lenses and invisibility cloaks, says Michigan Tech's Elena Semouchkina.

Credit: Navid Ganji, Michigan Tech

So she and her team set about investigating those complications and discovered that the magic of metamaterials is driven by more than just one mechanism of physics. A paper describing their research was recently published online by the Journal of Physics D: Applied Physics.

Simple!

Metamaterials may seem complex and futuristic, but the opposite is closer to the truth, says Semouchkina. Metamaterials ("meta" is the Greek word for "beyond") are engineered materials that have properties not found in nature. They are typically built of multiple identical elements fashioned from conventional materials, such as metals or nonconductive materials. Think of a Rubik's cube made of millions of units smaller than the thickness of a human hair.

These designer materials work by bending the paths of electromagnetic radiation--from radio waves to visible light to high-energy gamma rays--in new and different ways. How metamaterials bend those paths--a process called refraction--drives their peculiar applications. For example, a metamaterial invisibility cloak would bend the paths of light waves around a cloaked object, accelerating them on their way, and reunite them on the other side. Thus, an onlooker could see what was behind the object, while the object itself would be invisible.

The conventional approach among metamaterials researchers has been to relate a metamaterial's refractive properties to resonance. Each tiny building block of the metamaterial vibrates like a tuning fork as the electromagnetic radiation passes through, causing the desired type of refraction.

But not that simple . . .

Semouchkina wondered if there might be additional factors involved in bending the paths of the waves.

"Metamaterials seem simple, but their physics is more complicated," she says, explaining that she and her team focused on dielectric metamaterials, which are built of elements that don't conduct electricity.

The team ran numerous computer simulations and made a surprising discovery: it was the shape and repetitive organization of the building blocks within the metamaterial--their periodicity--that affected the refraction. Resonance seemed to have little or nothing to do with it.

The metamaterials they studied had characteristics of another type of artificial material, photonic crystals. Like metamaterials, photonic crystals are made of many identical cells. In addition, they behave like the semiconductors used in electronics, except they transmit photons instead of electrons.

"We found that the properties that go along with being a photonic crystal can mask the resonance of metamaterials, to the point they can cause unusual refraction-- including negative refraction, which is necessary for the development of a perfect lens," Semouchkina says.

Back to Basics

So what does this mean for the scientists and engineers designing tomorrow's super materials?

"Basically, we need to recognize that some of these structures can exhibit properties of photonic crystals, and we need to take their physics into account," Semouchkina says. "It's an evolving field, and it's a lot more complicated than we've given it credit for."

Semouchkina's team is working on developing invisibility cloaks using photonic crystals, but she stresses that metamaterials research can have other real-world applications. One of her projects focuses on using metamaterial concepts to improve the sensitivity of magnetic resonance imaging (MRI), which could lead to better medical diagnostics and advances in biological research.

"This is a very practical outcome, compared to the Harry Potter stuff," she says.

Understanding the underlying physics of metamaterials will speed up the development of such devices.

Media Contact

Allison Mills
awmills@mtu.edu
906-487-2343

 @michigantech

http://www.mtu.edu 

Allison Mills | EurekAlert!

More articles from Physics and Astronomy:

nachricht Quantum optics allows us to abandon expensive lasers in spectroscopy
22.11.2017 | Lomonosov Moscow State University

nachricht Nano-watch has steady hands
22.11.2017 | University of Vienna

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>