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 A tale of two pulsars' tails: Plumes offer geometry lessons to astronomers
18.01.2017 | Penn State

nachricht Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>