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 Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: 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 >>>