Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physicists Break Color Barrier for Sending, Receiving Photons

01.10.2010
University of Oregon scientists have invented a method to change the color of single photons in a fiber optic cable. The laser-tweaked feat could be a quantum step forward for transferring and receiving high volumes of secured data for future generations of the Internet.

The proof-of-concept experiment is reported in a paper about work led by UO physicist Michael G. Raymer that appeared in the Aug. 27 issue of Physical Review Letters.

In a separate paper also published by the same journal on Sep. 15, Raymer and collaborators at the University of Bath in the United Kingdom tell how they added hydrogen and a short laser burst to a hollow "photonic crystal" fiber cable to create multiple colors, or wavelengths, of light. This paper, Raymer said, provides groundwork for future research in creating ultra-short light pulses.

The single-photon project, in which a dual-color burst of laser light was used to change the color of a separate single photon of light, is directly applicable to future Internet communications technology, said Raymer, the UO's Knight Professor of Liberal Arts and Sciences and author of a newly published textbook "The Silicon Web: The Physics Behind the Internet."

In the computing world, digital data now is contained as individual bits represented by many electrons and is transmitted using pulses of infrared light containing many photons. In quantum computing -- a futuristic technology -- data might be stored in individual electrons and photons. Such quantum techniques could make data 100-percent secure from hackers and expand the ability to search large databases, Raymer said.

"There is a need for more bandwidth, or data rate, in fiber optic networks," he said. "In today's fiber optic lines one frequency of light may carry a phone conversation, while others may carry TV channels or emails, all traveling in separate channels across the Internet. At the level of single photons, we would like to send data in different channels -- colors or wavelengths -- at the same time. Quantum memories based on electrons emit and absorb visible light -- for example, red," he said. "But the optical fibers we want to use -- such as those in the ground now -- are optimized to transmit infrared, not visible light."

In experiments led by Raymer's doctoral student Hayden J. McGuinness, researchers used two lasers to create an intense burst of dual-color light, which when focused into the same optical fiber carrying a single photon of a distinct color, causes that photon to change to a new color. This occurs through a process known as Bragg scattering, whereby a small amount of energy is exchanged between the laser light and the single photon, causing its color to change.

This process, demonstrated in the UO’s Oregon Center for Optics, is called quantum frequency translation. It allows devices that talk to one another using a given color of light to communicate with devices that use a different color.

The research was stimulated by work done earlier by Raymer’s collaborators: Colin McKinstrie at Alcatel-Lucent Bell Labs and Stojan Radic at the University of California, San Diego.

"Other researchers have done this frequency translation using certain types of crystals," Raymer said. "Using optical fibers instead creates the translated photons already having the proper shape that allows them to be transmitted in a communication fiber. Another big advantage of our technique is that it allows us to change the frequency of a single photon by any chosen amount. The objective is to convert a single photon from the color that a common quantum memory will deal with into an infrared photon that communication fibers can transmit. At the other end, it has to be converted back into the original color to go into the receiving memory to be read properly."

The second paper published by Raymer’s group focused on theoretical and experimental work at UO and at the University of Bath. It showed how to create an optical frequency comb in a hydrogen-filled optical fiber.

The optical frequency comb contains many precisely known colors or wavelengths of light, and can be used to measure the wavelength of light, much as a ruler with many tick marks can be used to measure distance.

The comb method was co-developed by John Hall of the National Institute of Standards and Technology, who won the Nobel Prize in Physics in 2005 for his work that led to the standard for measuring light frequencies.

By filling empty air holes in a hollow optical with hydrogen gas, researchers were able to change the color, or frequency, of light passing through. As a short burst of red laser passed through the gas, the hydrogen molecules were caused to vibrate, emitting strong light of many colors.

"In the first study, we worked with one photon at a time with two laser bursts to change the energy and color without using hydrogen molecules," he said. "In the second study, we took advantage of vibrating molecules inside the fiber interacting with different light beams. This is a way of using one strong laser of a particular color and producing many colors, from blue to green to yellow to red to infrared."

The laser pulse used was 200 picoseconds long. A picosecond is one-trillionth of a second. Combining the produced light colors in such a fiber could create pulses 200,000 times shorter -- a femtosecond (one quadrillionth of a second).

Such time scales could open the way to study biological processes at the level of atoms or possibly capture so-far-unseen activity in photosynthesis, Raymer said.

Co-authors with McGuinness and Raymer on the single-photon paper were McKinstrie and Radic. The National Science Foundation funded the project.

For the optical comb work, Raymer teamed with UO student doctoral Chunbai Wu and Y.Y. Wang, F. Couny and Fetah Benabid, all of the University of Bath. The NSF and the UK's Engineering and Physical Sciences Research Council supported the research through grants to Raymer and Benabid, respectively.

About the University of Oregon
The University of Oregon is a world-class teaching and research institution and Oregon's flagship public university. The UO is a member of the Association of American Universities (AAU), an organization made up of the 63 leading public and private research institutions in the United States and Canada. The UO is one of only two AAU members in the Pacific Northwest.

Contact: Jim Barlow, director of science and research communications, 541-346-3481, jebarlow@uoregon.edu

Source: Michael G. Raymer, professor of physics, 541-346-4785, raymer@uoregon.edu

Links:
Raymer Web page: http://oco.uoregon.edu/faculty/michael-raymer
Oregon Center for Optics: http://oco.uoregon.edu/
UO physics department: http://physics.uoregon.edu/

Jim Barlow | Newswise Science News
Further information:
http://www.uoregon.edu

More articles from Physics and Astronomy:

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology

nachricht Light rays from a supernova bent by the curvature of space-time around a galaxy
21.04.2017 | Stockholm University

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: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>