Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Improving on the amazing: Ames Laboratory scientists seek new conductors for metamaterials

25.04.2012
Scientists at the U.S. Department of Energy’s Ames Laboratory have designed a method to evaluate different conductors for use in metamaterial structures, which are engineered to exhibit properties not possible in natural materials. The work was reported this month in Nature Photonics.

Cloaking devices that hide planes from RADAR, microscopes that can see inside a single cell, and miniature antennae that measure only a few millimeters all sound like parts of a science fiction movie. But, within the span of the decade since they began their work, Ames Laboratory physicist Costas Soukoulis and his research team have moved these and other innovations from the realm of fiction closer to reality.


A model of a three-dimensional metamaterial. Ames Laboratory scientists developed a method to evaluate different conductors for use in metamaterial structures.

“Metamaterials have a few fundamentally new properties that may allow for many new applications,” said Soukoulis. For instance, natural materials refract light to the opposite side of the incidence normal, while metamaterials can refract light to the same side (left-handed materials), allowing imaging with a flat lens. Metamaterials are also capable of absorbing all light that hits them, reflecting none of it, creating perfect absorbers. The materials can even slow light. And what makes these properties even more interesting is that they can be adjusted to the needs of particular technologies.

“Usually, materials scientists are presented with a material, determine its properties and only then come up with a use for the material. But metamaterials work in the opposite direction,” said Soukoulis. “With metamaterials, we can think about what technology we’d like and what properties we want – perhaps properties unheard of before – and design the materials to exhibit those properties.”

Take, for example, the goal of creating super-efficient devices to harvest sunlight in solar energy products. Ideal materials for such a device would absorb 100 percent of the solar spectrum.

“In metamaterials, we can design both their magnetic and electric responses,” said Thomas Koschny, Ames Laboratory associate scientist. “Therefore, we can control the reflection at the interface of the metamaterial, which you cannot easily do in normal materials. In regular materials, particularly with the types of waves like light, materials have only an electric response, and they are always reflective. But, in a metamaterial, we can arrange the parts of the material so that the electric response equals the magnetic response, and the surface is reflection free and all waves go into the material.”

Other possible applications are “superlenses” that would allow us to use visible light to see molecules, like DNA molecules, in detail and devices that store large amounts of data optically. And many other potential uses exist because, unlike in natural materials, metamaterials can be designed to work at target frequencies, at least in principle, from radio frequencies to visible light.

But with such great potential also comes several challenges, some of which Soukoulis’ team have already made significant progress toward meeting. In 2006, the researchers were the first to fabricate a left-handed metamaterial, one with a negative index of refraction, in waves very close to visible light. In 2007, the group designed and fabricated the first left-handed metamaterial for visible light, and they recently fabricated chiral metamaterials that have giant optical activity.

Another challenge is reducing energy losses in metamaterials. Energy is lost by conversion to heat in their metallic components. In results reported in Nature Photonics this month, Soukoulis and his team evaluated a variety of conducting materials – including graphene, high-temperature superconductors and transparent conducting oxides.

“Graphene is a very interesting material because it is only a single atom thick and it is tunable, but unfortunately it does not conduct electrical current well enough to create an optical metamaterial out of it,” said Philippe Tassin, a postdoctoral research associate at Ames Laboratory. “We also thought high-temperature superconductors were very promising, but we found that silver and gold remain the best conductors for use in metamaterials.”

While neither graphene nor superconductors will immediately fix losses in metamaterials, Soukoulis’ work provides a method for evaluating future candidates to replace gold or silver that will help harness the enormous potential of metamaterials.

“Metamaterials may help solve the energy problems America is facing,” said Soukoulis. “There’s no shortage of new ideas in the field of metamaterials, and we’re helping make progress in understanding metamaterials’ basic physics, applied physics and possible applications.”

The research was funded by DOE’s Office of Science.

The Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. The Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov

Breehan Gerleman Lucchesi | EurekAlert!
Further information:
http://www.ameslab.gov

More articles from Physics and Astronomy:

nachricht Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>