Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultra-Simple Desktop Device Slows Light to a Crawl

01.04.2003


Though Einstein put his foot down and demanded that nothing can move faster than light, a new device developed at the University of Rochester may let you outpace a beam by putting your foot down on the gas pedal. At 127 miles per hour, the light in the new device travels more than 5 million times slower than normal as it passes through a ruby just a few centimeters long.



Instead of the complex, room-filling mechanisms previously used to slow light, the new apparatus is small and, in the words of its creator, "ridiculously easy to implement." Such a simple design will likely pave the way for slow light, as it is called, to move from a physical curiosity to a useful telecommunications tool. The research is being published in this week’s Physical Review Letters.

The new technique uses a laser to "punch a hole" in the absorption spectrum of a common ruby at room temperature, and a second laser shines through that hole at the greatly reduced speed. A recent successful attempt to slow light to these speeds used a Bose-Einstein condensate (BEC), a state of matter existing 459 degrees below zero Fahrenheit where all atoms act in unison like a single, giant atom. The laser shining through the BEC was slowed to 38 miles per hour, but the system had enormous drawbacks, not the least of which was that the equipment needed to create the BEC wouldn’t fit in the average living room, and the created BEC itself was little bigger than the head of a pin.


"If that was the world’s hardest way to slow down light, then what we’ve found is the world’s easiest way to do it," says Robert Boyd, the M. Parker Givens Professor of Optics at the University. "We can slow light just as much in a space the size of a desktop computer."

Slowing light, at least a little, isn’t as difficult as it may seem. Light passing through a window is 1.5 times slower while moving through the glass, and is slowed slightly less so when passing through water. But to achieve the 5.3-million fold slowdown, Boyd and his team, students Matthew Bigelow and Nick Lepeshkin, used a quantum quirk called "coherent population oscillations" to create a special gap in the frequencies of light that a ruby absorbs. Rubies are red because they absorb most of the blue and green light that strikes them. Shining an intense green laser at the ruby partially saturates the chromium ions that give ruby its red color. They then shine a second beam, called the probe laser, into the ruby. The probe beam has a frequency slightly different than the first laser, and these offset frequencies interact with each other, causing variations the same way two ripples encountering each other on a pond might create waves higher and lower than either one had alone. The chromium ions respond to this new frequency of rhythmic highs and lows by oscillating in sympathy. One consequence of this oscillation is that it allows the probe laser to pass through the ruby, even though the laser is green, but it only allows it to pass 5.3 million times more slowly than light would otherwise travel.

Boyd anticipates that the slow light device will find a role in the telecommunications industry. When two signals from fiber optic lines merge, the two signals may reach the merging router at the exact same moment and need to be separated slightly in time so they can be laid down one after another. Like two cars merging on a highway where one may need to slow down to let another car into the lane, a light-slowing device could help ease congestion on fiber optic lines and simplify the process of merging signals on busy networks.

One drawback to the new technique is currently being scrutinized by Boyd and his coworkers-the duration of the pulses of light that it delays are very long. The BEC experiments were able to delay a short pulse, which meant that a plain pulse of light and a slowed pulse would differ by several times the pulses’ lengths. The Boyd technique slows light by roughly the same amount as the BEC method, but since the pulses are much larger, the delay is only a fraction of the pulses’ size. It would be the difference between slowing an economy car a few feet to let another economy car merge, and a double-tractor trailer slowing only a few feet and expecting another double trailer to merge into the gap. Boyd suspects that different materials may yield slowed light that can transmit shorter pulses that would be more useful for telecommunications work.

Jonathan Sherwood | EurekAlert!
Further information:
http://www.rochester.edu/pr/News/NewsReleases/scitech/boyd-slowlight.html

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>