Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A feeling for the (light) wave

13.01.2014
A team at the Laboratory for Attosecond Physics has designed and built a simplified detector for the measurement of the waveforms of pulsed laser radiation.

A team in the Laboratory for Attosecond Physics (LAP) at the Max-Planck-Institute of Quantum Optics has taken another step toward the achievement of complete control over the waveform of pulsed laser light.


A mode-locked laser at the Max-Planck-Institute of Quantum Optics emits flashes of light that last for a few femtoseconds. A new glass-based phase detector now enables simpler and more precise control of their waveforms. (Graphic: Thorsten Naeser)

Together with colleagues based at LMU and the Technische Universität München (TUM), they have constructed a detector which provides a detailed picture of the waveforms of laser pulses that last for a few femtoseconds.

Unlike conventional gas-phase detectors, this one is made of glass, and measures the flow of electric current between two electrodes that is generated when the electromagnetic field associated with the laser pulse impinges on the glass.

The researchers can then deduce the precise waveform of the pulse from the properties of the induced current. Knowledge of the exact waveform of the femtosecond pulse in turn makes it possible to reproducibly generate light flashes that are a thousand times shorter – lasting only for attoseconds – and can be used to study ultrafast processes at the molecular and atomic levels (Nature Photonics, DOI:10.1038/nphoton.2013.348, 12 January 2014).

Modern mode-locked lasers are capable of producing extremely brief light flashes that last for only a few femtoseconds (1 fs is one-millionth of a billionth of a second). With durations of as little as 2.5 fs, such pulses correspond very few oscillations of the electromagnetic field, indeed to only 1 to 2 complete cycles, which are however preceded and followed by waves of lower amplitude that are rapidly attenuated. In laser physics it is often important to know more about the precise form of the high-amplitude oscillations, because this tells one the shape of the electromagnetic fields and allows them to be utilized in an optimal manner to probe ultrashort processes that occur at the level of molecules and atoms.

A team led by Prof. Ferenc Krausz and including his doctoral student Tim Paasch-Colberg has now developed a glass-based detector that allows one to accurately determine the form of the light waves that make up an individual femtosecond pulse. In the course of experiments performed over the past several years, physicists in the group have learned that when pulsed high-intensity laser light impinges on glass, it induces measurable amounts of electric current in the material (Nature, 3 January 2013). Krausz and his colleagues have now found that the direction of flow of the current generated by an incident femtosecond pulse is sensitively dependent on the exact form of its wave packet.

In order to calibrate the new glass detector, the researchers coupled their system with a conventional instrument used to measure waveforms of light. Since the energy associated with the laser pulse is sufficient to liberate bound electrons from atoms of a noble gas such as xenon, the “classical” detector measures the currents caused by the motions of these free electrons. But there is a catch – the measurements must be done in a high vacuum. By comparing the currents induced in the new solid-state detector with the data obtained using the conventional apparatus, the team was able to characterize the performance of their new glass-based set-up, so that it can now be used as a reliable phase detector for few-cycle femtosecond laser pulses. The new instrument enormously simplifies measurements in the domain of ultrafast physical processes, because one can dispense with the use of cumbersome vacuum chambers. Moreover, in its practical application the technique is much more straightforward than the methods available for the mapping of waveforms hitherto.

If the precise waveform of the femtosecond laser pulse is known, it becomes possible to reproducibly generate stable trains of ultrashort attosecond light flashes, each one a thousand times shorter than the pulse used to induce them. The composition of the attosecond flashes is in turn highly dependent on the exact shape of the femtosecond pulses. Attosecond flashes can be used to “photograph” the motions of electrons in atoms or molecules. In order to obtain high-resolution images, the length of the flashes must be tuned to take account of the material one wants to investigate.

Highly sensitive and reliable measurements of physical processes at the level of the microcosmos with the aid of single attosecond light flashes of known shape should become easier to perform because, thanks to the new glass-based phase detector, the source of the energy to drive them – the waveform of the laser pulses – can now be controlled much more easily than before. Thorsten Naeser

Original publication:

Tim Paasch-Colberg, Agustin Schiffrin, Nicholas Karpowicz, Stanislav Kruchinin, Özge Saglam, Sabine Keiber, Olga Razskazovskaya, Sascha Mühlbrandt, Ali Alnaser, Matthias Kübel, Vadym Apalkov, Daniel Gerster, Joachim Reichert, Tibor Wittmann, Johannes V. Barth, Mark I. Stockman, Ralph Ernstorfer, Vladislav S. Yakovlev, Reinhard Kienberger and Ferenc Krausz
Solid-state light-phase detector
Nature Photonics, DOI:10.1038/nphoton.2013.348, 12 January 2014
For more information please contact:
Tim Paasch-Colberg
Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1, 85748 Garching, Germany
Phone: +49 (0)89 / 32 905 -651
E-mail: tim.paasch-colberg@mpq.mpg.de.de
Prof. Ferenc Krausz
Chair of Experimental Physics, Ludwig-Maximilians-Universität München
Laboratory for Attosecond Physics
Director at the Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching, Germany
Phone: +49 (0)89 / 32 905 -600
E-mail: ferenc.krausz@mpq.mpg.de
Dr. Olivia Meyer-Streng
Press & Public Relations
Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1, 85748 Garching, Germany
Phone: +49 (0)89 / 32 905 -213
E-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut
Further information:
http://www.attoworld.de
http://www.mpq.mpg.de

More articles from Physics and Astronomy:

nachricht Spiral arms: not just in galaxies
30.09.2016 | Max-Planck-Institut für Radioastronomie

nachricht Discovery of an Extragalactic Hot Molecular Core
29.09.2016 | National Astronomical Observatory of Japan

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: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

The structure of the BinAB toxin revealed: one small step for Man, a major problem for mosquitoes!

30.09.2016 | Life Sciences

Researcher creates a controlled rogue wave in realistic oceanic conditions

30.09.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>