Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Catching the wave -- Researchers measure very short laser pulses

04.12.2006
Scientists have perfected a technique for very accurately measuring and controlling the electromagnetic waves within some of the shortest laser pulses ever made, says new research published today. Being able to fully understand and control these laser pulses represents an important step towards using them to track and manipulate electrons in leading-edge research at the sub-atomic level.

The study, published in Nature Physics, focused on extremely short laser pulses, less than 10 femtoseconds long - a femtosecond is one million-billionth of a second. These laser pulses can allow scientists to move and control the electrons in atoms and molecules, and to understand, for example, how molecules are formed. To achieve this reliably, the pulse of electromagnetic waves emitted from the laser must be controlled and measured with a precision which, until now, has been very hard to achieve.

The team of physicists from Imperial College London attained an unprecedented level of accurate measurement by firing the femtosecond laser pulse into a sample of gas, which responds by emitting an x-ray pulse which is even shorter in duration - up to 10 times shorter than the original laser pulse. The researchers found that the spectrum of the x-ray pulse has encoded within it all the information necessary to precisely reconstruct the waveform of the original laser pulse. Through careful measurements and some 'intelligent' software designed specifically for this purpose, the researchers were therefore able, for the first time, to measure the waveform of individual femtosecond pulses.

Dr John Tisch, one of the Imperial research team, said: "This measurement technique is so accurate that we can determine the position of a peak in the pulse of electromagnetic waves from the laser with a precision of a mere 0.05 femtoseconds - in other words, 50 attoseconds. Also, the measurement can be made on individual pulses rather than by looking at the average properties of many pulses, so this is an important step forwards."

Dr Tisch explains that not only will this new technique lead to a greater ability to use short laser pulses for accurate sub-atomic level research, but it also sheds new light on the extremely short x-ray pulses emitted in response: "The x-ray pulses we used in the measurement process of our research are of great interest in their own right," he says. "They are on the attosecond timescale, which is even shorter than a femtosecond - just one billion-billionth of a second. They are a new tool for scientists to probe even faster motion than the femtosecond pulses that triggered them."

The research team have recently received a four-year £2.5 million grant from the EPSRC to take this research to the next stage. Professor Jonathan Marangos explains: "Now we've perfected this technique, we are going to look into using our accurate measurements and control of these lasers to manipulate electrons and control quantum processes."

Laura Gallagher | EurekAlert!
Further information:
http://www.imperial.ac.uk

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of 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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>