Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Light bursts out of a flying mirror

24.04.2013
An international team of researchers succeeds in generating flashes of extreme ultraviolet radiation via the reflection from a mirror that moves close to the speed of light.

A dense sheet of electrons accelerated to close to the speed of light can act as a tuneable mirror that can generate bursts of laser-like radiation in the short wavelength range via reflection.


A laser pulse (red, bottom), liberates electrons (green) from the carbon atoms of a nanometer-thin foil and accelerates them to close to the speed of light. An infrared light pulse impinges on the electron layer from the opposite direction and reflects off the electron mirror as a light burst in the extreme ultraviolet with a duration of only a few hundred attoseconds. Picture: Thorsten Naeser

A team of physicists from the Max-Planck-Institute of Quantum Optics (MPQ) in Garching, the Ludwig-Maximilians-Universität (LMU) München, the Queens University Belfast (QUB) and the Rutherford Appleton Laboratory (RAL) near Oxford created such a mirror in a recent experiment. The scientists used an intense laser pulse to accelerate a dense sheet of electrons from a nanometre-thin foil to close to the speed of light and reflected a counter-propagating laser pulse from this relativistic mirror.

With this experiment, the physicists managed to carry out a Gedankenexperiment (thought experiment) formulated in 1905 by Albert Einstein stating that the reflection from a mirror moving close to the speed of light could in principle result in bright light pulses in the short wavelength range. The researchers report on their results in Nature Communications, 23. April, 2013.

In everyday life, reflections of light are usually observed from surfaces that are at rest such as the reflection from a piece of glass or a smooth surface of water. But, what happens if one creates a mirror moving incredibly fast, close to the speed of light? This question was answered more than a century ago by Albert Einsteins in 1905 in his theory of special relativity. Now, an international team of researchers investigated that question in an experiment.

In the experiment conducted at the Rutherford Appleton Laboratory near Oxford the physicists irradiated a nanometre-thin, freestanding foil with a 50 femtosecond short, ultra-intense laser pulse (one femtosecond is a millionth of a billionth of a second). The impinging laser pulse liberated electrons from the carbon atoms of the foil and rapidly accelerated to close to the speed of light in less than a micrometer forming a dense sheet of electrons capable of acting as a mirror. “This mirror structure is stable for only a few femtoseconds“, explains Daniel Kiefer, who wrote his Dissertation on this topic. Within this extremely short life time the scientists shot a secondary laser pulse with a wavelength in the near infrared (800 nm) and a pulse duration of several femtoseconds from the opposite direction on the generated relativistic mirror structure.

In stark contrast to a mirror at rest, light reflected from a mirror that is moving is changed in its colour (that is in its wavelength) as the reflected photons gain momentum from the mirror. This process is very similar to a ball that bounces off a racket and thereby accelerates to higher speed. However, instead of moving faster (photons already travel at the speed of light), the reflected light is shifted in its frequency. This phenomenon is very similar to the Dopplereffect observed from an ambulance siren, which sounds higher (louder) or deeper (quieter) depending on whether the ambulance is moving towards or away from the observer. In the experiment, the incredibly high velocity of the electron mirror gave rise to a change in frequency upon reflection from the near infrared to the extreme ultraviolet up to a wavelength of 60 to 80 nanometre. Moreoever, the time duration of the reflected pulses was on the order of a few hundred attoseconds only (one attosecond is a billionth of a billionth of a second).

This experiment not only supports Albert Einstein’s theory of special relativity, but in fact paves the way for a new method to generate intense, attosecond short flashes of light. Those pulses would allow the electron motion in atoms to be resolved thus giving deep insight into elementary processes in nature, which are so far largely unexplored.

For Prof. Schreiber and his group at the LMU, this is only the very beginning. Our laser systems will advance in the future delivering even more powerful pulses with higher repetition rate and shorter pulse duration. This scheme will benefit strongly from those developments in laser technology and thus may enable the generation of laser-like radiation with even higher intensity and shorter wavelength ideal to explore the microcosm. “The relativistic mirror has high potential in the next years“, Schreiber concludes. Thorsten Naeser
Publication:
D. Kiefer, M. Yeung, T. Dzelzainis, P.S. Foster, S.G. Rykovanov, C.L. S. Lewis, R. Marjoribanks, H. Ruhl, D. Habs, J. Schreiber, M. Zepf & B. Dromey
Relativistic electron mirrors from nanoscale foils for coherent frequency upshift to the extreme ultraviolet.
Nature Communications, DOI: 10.1038/ncomms2775, 23. April 2013.

For more information please contact:

Dr. Daniel Kiefer
Ludwig-Maximilians-Universität München
Fakultät für Physik, Am Coulombwall 1
85748 Garching
Phone: +49 (0)89 / 289 -540 23
E-mail: daniel.kiefer@mpq.mpg.de

Prof. Dr. Jörg Schreiber
Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching
Phone: +49 (0)89 / 289 -540 25
E-mail: joerg.schreiber@mpq.mpg.de

Dr. Olivia Meyer-Streng
Press & Public Relations
Max-Planck-Institute of Quantum Optics, Garching
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.mpq.mpg.de

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 >>>