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 When helium behaves like a black hole
22.03.2017 | University of Vermont

nachricht Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars
22.03.2017 | International Centre for Radio Astronomy Research

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>