Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Design Nanometer-Scale Material That Can Speed Up, Squeeze Light

02.05.2013
In a process one researcher compares to squeezing an elephant through a pinhole, researchers at Missouri University of Science and Technology have designed a way to engineer atoms capable of funneling light through ultra-small channels.

Their research is the latest in a series of recent findings related to how light and matter interact at the atomic scale, and it is the first to demonstrate that the material – a specially designed “meta-atom” of gold and silicon oxide – can transmit light through a wide bandwidth and at a speed approaching infinity. The meta-atoms’ broadband capability could lead to advances in optical devices, which currently rely on a single frequency to transmit light, the researchers say.

“These meta-atoms can be integrated as building blocks for unconventional optical components with exotic electromagnetic properties over a wide frequency range,” write Dr. Jie Gao and Dr. Xiaodong Yang, assistant professors of mechanical engineering at Missouri S&T, and Dr. Lei Sun, a visiting scholar at the university. The researchers describe their atomic-scale design in the latest issue of the journal Physical Review B (“Broadband epsilon-near-zero metamaterials with steplike metal-dielectric multilayer structures,” Phys. Rev. B 87, 165134 2013).

The researchers created mathematical models of the meta-atom, a material 100 nanometers wide and 25 nanometers tall that combined gold and silicon oxide in stairstep fashion. A nanometer is one billionth of a meter and visible only with the aid of a high-power electron microscope.

In their simulations, the researchers stacked 10 of the meta-atoms, then shot light through them at various frequencies. They found that when light encountered the material in a range between 540 terahertz and 590 terahertz, it “stretched” into a nearly straight line and achieved an “effective permittivity” known as epsilon-near-zero.

Effective permittivity refers to the ratio of light’s speed through air to its speed as it passes through a material. When light travels through glass, for instance, its effective permittivity is 2.25. Through air or the vacuum of outer space, the ratio is one. That ratio is what is typically referred to as the speed of light.

As light passes through the engineered meta-atoms described by Gao and Yang, however, its effective permittivity reaches a near-zero ratio. In other words, through the medium of these specially designed materials, light actually travels faster than the speed of light. It travels “infinitely fast” through this medium, Yang says.

The meta-atoms also stretch the light. Other materials, such as glass, typically compress optical waves, causing diffraction.

This stretching phenomenon means that “waves of light could tunnel through very small holes,” Yang says. “It is like squeezing an elephant through an ultra-small channel.”

The wavelength of light encountering a single meta-atom is 500 nanometers from peak to peak, or five times the length of Gao and Yang’s specially designed meta-atoms, which are 100 nanometers in length. While the Missouri S&T team has yet to fabricate actual meta-atoms, they say their research shows that the materials could be built and used for optical communications, image processing, energy redirecting and other emerging fields, such as adaptive optics.

Last year, Albert Polman at the FOM Institute for Atomic and Molecular Physics in Amsterdam and Nader Engheta, an electrical engineer at the University of Pennsylvania, developed a tiny waveguide device in which light waves of a single wavelength also achieved epsilon-near-zero. But the Missouri S&T researchers’ work is the first to demonstrate epsilon-near-zero in a broadband of 50 terahertz.

“The design is practical and realistic, with the potential to fabricate actual meta-atoms,” says Gao. Adds Yang: “With this research, we filled the gap from the theoretical to the practical.”

Through a process known as electron-beam deposition, the researchers have built a thin-film wafer from 13 stacked meta-atoms. But those materials were uniform in composition rather than arranged in the stairstep fashion of their modeled meta-atoms.

Andrew Careaga | EurekAlert!
Further information:
http://www.mst.edu

More articles from Materials Sciences:

nachricht Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>