Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. Space Industry and Business News .




TECH SPACE
Photon recoil provides new insight into matter
by Staff Writers
Brunswick, Germany (SPX) Feb 04, 2014


This is a schematic representation of the experimental set-up for photon-recoil spectroscopy. An auxiliary ion (the logic ion, blue) is trapped in an ion trap together with the ion to be investigated (the spectroscopy ion, red). The logic ion is cooled down to the ground state of motion by means of laser cooling (cooling laser and logic laser). Due to the strong coupling of the two ions, the spectroscopy ion is cooled along with the logic ion. The spectroscopy ion is then excited by means of laser pulses (spectroscopy/repump laser), which puts both ions into motion. This motion represents the spectroscopy signal and can be read out via the logic ion (logic laser, cooling laser) which becomes dark in the event of motion. Image courtesy PTB.

Quantum logic spectroscopy - which is closely linked with the name of the 2012 Nobel prize laureate, David J. Wineland - has been significantly extended: this new method is called "photon-recoil spectroscopy" (PRS).

The potential of this method has been demonstrated by the research group led by Piet Schmidt from the QUEST Institute, which is based at the Physikalisch-Technische Bundesanstalt, together with colleagues from Leibniz University Hannover. In contrast to the original quantum logic technique, the new method enables the investigation of very fast transitions in atoms or molecules.

The results have been published in the current edition of Nature Communications. With this new method, spectroscopic investigations will be possible on nearly any kind of particles. The only condition is that they absorb just a few photons from a laser beam.

This not only allows extremely accurate frequency measurements, but also increases the chances of finding discrepancies in observations of a possible change in the fine-structure constant. Furthermore, numerous other applications will arise, for instance in astronomy or chemistry.

Piet Schmidt is a former colleague of David Wineland's. He worked in the research group of the Noble prize laureate for some time at the National Institute of Standards and Technology (NIST) (PTB's counterpart in the USA) and was involved in the development of quantum logic spectroscopy (QLS) there.

At that time, the comparison of astronomic spectra and laboratory spectra had already indicated that the fine-structure constant may have changed. The significance of those measurements was, however, limited since the laboratory spectra of the metal ions were not sufficiently well known.

"Since no sufficiently precise spectroscopic method existed for these ions at the time, I came up with the idea of photon-recoil spectroscopy (PRS) as an extension of quantum logic spectroscopy. This method allows a precise investigation of these ions", Schmidt says.

"Similar to quantum logic spectroscopy, we capture the ion that we want to investigate in a trap together with an auxiliary ion", Yong Wan (the first author of the study) explains. The experiment was carried out in a sophisticated set-up consisting of a pair of two closely coupled ions - a calcium ion and a magnesium ion.

The two ions repel each other due to their electric charge, but are kept together by the ion trap and are thus forced to do everything together, similar to a pair of twins. The researchers exploit this circumstance to obtain information on the ion they want to investigate (the spectroscopy ion, in their experiment, the calcium ion) by observing the behaviour of the easily controllable second ion (auxiliary or logic ion, in their case, the magnesium ion).

Wan illustrates the principle as follows: "Just imagine a child sitting on a swing at rest. You throw the child a ball, and then more balls, each of them exactly at times when the swing is moving particularly fast. The swing is thus excited into very strong oscillations. This is exactly the same with laser light pulses when we direct them at our ion pair: if they have the suitable frequency, the photons are absorbed and cause the spectroscopy ion to oscillate due to the recoil kick. Because it is strongly coupled to the auxiliary ion, the latter also oscillates simultaneously."

To stick to the image of the child: now two children are sitting on two swings next to each other, they hold onto each other and are unable to let go. "The auxiliary ion allows us to detect the oscillation of the spectroscopy ion very efficiently, since we can control the former very accurately and observe it - in contrast to the spectroscopy ion", Wan explains. The small signal of the spectroscopy ion is amplified via the auxiliary ion. "This makes our method much more sensitive than if we were to detect the photons themselves, as has mostly been the case with the previous spectroscopic techniques."

Previously, thousands of photons had to be scattered by the ion to obtain a meaningful signal. "Our method requires merely ten photons to give the same signal", Florian Gebert (co-autor of the investigation) explains.

After researchers from Innsbruck, Austria, showed in a similar experiment - a few months ago - that even single photons can be detected in this way, Schmidt's group has now demonstrated that quantum recoil spectroscopy is indeed very accurate. Hereby, the collaboration with Klemens Hammerer's group from Leibniz University Hannover was of central importance. "Thanks to their analytical model, systematic shifts of the observed signal could be accurately predicted", Schmidt says.

In this way, Wan and his colleagues have measured the frequency of a certain transition in calcium to an accuracy of 88 kHz. Previous measurements were less precise by more than an order of magnitude.

A special feature of the technique is its flexibility: "We only need to change the spectroscopy ion and to tune the spectroscopy laser to be able to investigate the next ion species. The auxiliary ion and the complex laser set-up it requires remain unchanged", Schmidt explains. His objective is - typical of PTB - to carry out absolute frequency measurements of many different ions with greatest possible precision.

Contrary to the original quantum logic spectroscopy, the new technique allows the investigation of ions which remain in their excited state for a few micro- or even nano-seconds only. This considerably extends the range of applications accessible.

Together with the greater sensitivity, this opens up new possibilities in the precision spectroscopy of molecular and metal ions which are found in space and are often used as reference by astronomers. This is good news, for example, for the researchers who compare ancient quasar light with "new" light in order to detect possible changes in the fine-structure constant.

Technically speaking, these scientists do not investigate the light itself, but the characteristic spectra of the elements which are traversed by the light. These and further astronomic investigations will become more accurate thanks to Schmidt's measurements. "Our method is so versatile that a lot of other applications in astronomy or chemistry will come up", Schmidt expects.

Y. Wan, F. Gebert, J.B. Wubbena, N. Scharnhorst, S. Amairi, I.D. Leroux, B. Hemmerling, N. Lorch, K. Hammerer, P.O. Schmidt: Precision spectroscopy by photon-recoil signal amplification. Nature communications. DOI: 10.1038/ncomms4096

.


Related Links
Physikalisch-Technische Bundesanstalt (PTB)
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TECH SPACE
Faster X-ray technology paves the way for better catalysts
Hamburg, Germany (SPX) Feb 04, 2014
By using a novel X-ray technique, researchers have observed a catalyst surface at work in real time and were able to resolve its atomic structure in detail. The new technique, pioneered at DESY's X-ray light source PETRA III, may pave the way for the design of better catalysts and other materials on the atomic level. It greatly speeds up the determination of atomic surface structures and e ... read more


TECH SPACE
Oman orders NASAMS air defense system

A Proposal For The Space Debris Society

Storage system for 'big data' dramatically speeds access to information

Raytheon secures first international customer for its F-16 RACR AESA radar

TECH SPACE
MUOS Satellite Tests Show Extensive Reach In Polar Communications Capability

US Marines Reach Milestone For New General Dynamics-built Aviation CCS

Space squadron optimizes wideband communication constellations

GA-ASI and Northrop Showcase Unmanned Electronic Attack Capabilities

TECH SPACE
The go-ahead is given for Arianespace's February 6 flight with Ariane 5

SpaceX's next cargo mission to space station is Mar 16

Both payloads for Arianespace's next Ariane 5 flight are mated to the launcher

45th Space Wing Supports NASA Launch

TECH SPACE
Lockheed Martin Powers On Second GPS 3 Satellite In Production

India to launch three navigation satellites this year

NGC Wins Contract For GPS-Challenged Navigation and Geo-Registration Solution

20th Anniversary of Initial Operational Capability of the GPS Constellation

TECH SPACE
USAF Receives First B-1 Equipped with Boeing Integrated Battle Station

Launching the Fastest Plane of the Future

Canadian firm buys British, U.S. landing-gear manufacturing operations

USAF Orders Additional Boeing Combat Survivor Evader Locators

TECH SPACE
Integration brings quantum computer a step closer

New quantum dots herald a new era of electronics operating on a single-atom level

Dutch hi-tech group ASML profits dip despite record sales

2-proton bit controlled by a single copper atom

TECH SPACE
High resolution, digital bathymetry now available off-the-shelf

Savanna vegetation predictions best done by continent

Chinese scientists pinpoint source of Yangtze's main tributary

China to promote geological information industry

TECH SPACE
Asian ozone pollution in Hawaii is tied to climate variability

Cooperative SO2 and NOx aerosol formation in haze pollution

Made in China for us: Air pollution tied to exports

Delhi says air 'not as bad' as Beijing after smog scrutiny




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement