Physicist Costas Soukoulis and his research group at the U.S. Department of Energy’s Ames Laboratory on the Iowa State University campus are having the time of their lives making light travel backwards at negative speeds that appear faster than the speed of light. That, folks, is a mind-boggling 186,000 miles per second – the speed at which electromagnetic waves can move in a vacuum. And making light seem to move faster than that and in reverse is what Soukoulis, who is also an ISU Distinguished Professor of Liberal Arts and Sciences, said is “like rewriting electromagnetism.” He predicted, “Snell’s law on the refraction of light is going to be different; a number of other laws will be different.”
However, neither Soukoulis nor any other scientist involved in efforts to manipulate the direction and speed of light can do so with naturally occurring materials. The endeavor requires exotic, artificially created materials. Known as metamaterials, these substances can be manipulated to respond to electromagnetic waves in ways that natural materials cannot. Natural materials refract light, or electromagnetic radiation, to the right of the incident beam at different angles and speeds. However, metamaterials, also called left-handed materials, make it possible to refract light at a negative angle, so it emerges on the left side of the incident beam. This backward-bending characteristic of metamaterials allows enhanced resolution in optical lenses, which could potentially lead to the development of a flat superlens with the power to see inside a human cell and diagnose disease in a baby still in the womb.
The challenge that Soukoulis and other scientists face who work with metamaterials is to fabricate them so that they refract light negatively at ever smaller wavelengths, with the ultimate goal of making a metamaterial that refracts light at visible wavelengths and achieving the much-sought-after superlens. Admittedly, that goal is a ways off. To date, existing metamaterials operate in the microwave or far infrared regions of the electromagnetic spectrum. The near infrared region of the spectrum still lies between the microwave and visible regions, and the wavelengths become ever shorter moving along the electromagnetic spectrum to visible light. Correspondingly, to negatively refract light at these shorter wavelengths requires fabricating metamaterials at extremely small length scales – a tricky feat.
However, recent research by Soukoulis and his co-workers from the University of Karlsruhe, Germany, published in the May 12, 2006, issue of Science demonstrates they have done just that. “We have fabricated for the first time a metamaterial that has a negative index of refraction at 1.5 micrometers,” said Soukoulis. “This is the smallest wavelength obtained so far.” Small, indeed; these wavelengths are microscopic and can be used in telecommunications. Soukoulis’ success moves metamaterials into the near infrared region of the electromagnetic spectrum – very close to visible light, superior resolution and a wealth of potential applications!
In addition, Soukoulis and his University of Karlsruhe colleagues have also shown that both the velocity of the individual wavelengths, called phase velocity, and the velocity of the wave packets, called group velocity, are both negative, which Soukoulis said accounts for the ability of negatively refracted light to seemingly defy Einstein’s theory of relativity and move backwards faster than the speed of light.Elaborating, Soukoulis said, “When we have a metamaterial with a negative index of refraction at 1.5 micrometers that can disperse, or separate a wave into spectral components with different wavelengths, we can tune our lasers to play a lot of games with light. We can have a wavepacket hit a slab of negative index material, appear on the right-hand side of the material and begin to flow backward before the original pulse enters the negative index medium.”
Continuing, he explained that the pulse flowing backward also releases a forward pulse out the end of the medium, a situation that causes the pulse entering the front of the material appear to move out the back almost instantly.
“In this way, one can argue that that the wave packet travels with velocities much higher than the velocities of light,” said Soukoulis. “This is due to the dispersion of the negative index of refraction; there is nothing wrong with Einstein’s theory of relativity.” (These effects are clearly seen in the simulations that accompany this press release. Go to: Light Movies)
The Basic Energy Sciences Office of the DOE’s Office of Science funds Ames Laboratory’s research on metamaterials. Ames Laboratory is operated for the Department of Energy by Iowa State University. The Lab conducts research into various areas of national concern, including energy resources, high-speed computer design, environmental cleanup and restoration, and the synthesis and study of new materials.
Saren Johnston | EurekAlert!
Neutron star merger directly observed for the first time
17.10.2017 | University of Maryland
Breaking: the first light from two neutron stars merging
17.10.2017 | American Association for the Advancement of Science
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Life Sciences
17.10.2017 | Earth Sciences