Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Electrons surfing on a laser beam


The largest particle accelerator in the world – the Large Hadron Collider at CERN in Switzerland – has a circumference of around 26 kilometres. Researchers at Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany, are attempting to go to the other extreme by building the world's smallest machine of this kind – a particle accelerator that fits on a microchip. The research team has now taken another step towards achieving this ambition.

The fundamental idea behind the miniature particle accelerator’s development is to enable scientists to use laser beams to accelerate electrons. What sounds deceptively simple in theory raises a whole series of challenges in practice, extending across various fields of physics.

For example, the scientists need to be able to control the oscillation of light and the movement of electrons with great precision in order to ensure that they meet each other at just the right moment.

One way of envisaging this is to imagine a ship on a stormy sea; to safely ascend the wave and come down on its other side, the helmsman has to watch the oncoming wave and judge when it will meet the vessel.

It is equally crucial for the FAU’s team of scientists to ascertain when and where the maximum crest of a light wave will hit a packet of electrons so that they can influence the outcome to a highly specific degree. This means they need to enable light and electrons to coincide within ‘attoseconds’ – that is, a billionth of a billionth of a second.

In an exciting first, this is exactly what the research group around FAU’s Prof. Dr. Peter Hommelhoff have succeeded in achieving. The team has developed a new technique involving the intersection of two laser beams oscillating at different frequencies in order to generate an optical field whose properties the researchers can influence to an extremely precise degree.

The key property of this optical field is that it retains contact with the electrons, effectively moving with them – hence its being termed a travelling wave – so the electrons can continuously sense, or ‘surf’, the optical field. In this way, the optical field transmits its properties exactly to the particles.

Not only does this process cause the particles to precisely reflect the field structure, it also accelerates them – to a strikingly high degree. This effect is crucial to the miniature particle accelerator’s practical application, as it relates to how much energy can be transferred to the electrons across what distance. The acceleration gradient, which indicates the maximum measured electron energy gain versus distance covered, reaches the extremely high value of 2.2 giga-electron-volts per metre, much higher than that attained by conventional accelerators.

However, the acceleration distance of only 0.01 millimetres currently available to the research team in Erlangen is not sufficient for them to generate the energy needed for achieving results of relevance to practical applications. ‘Despite this, for particle accelerators in medicine, we would only need a tiny acceleration length of less than a millimetre,’ explains Dr Martin Kozák, who carried out the laboratory experiment.

Particle accelerator on a microchip

Project lead Prof. Dr. Peter Hommelhoff of the Chair of Laser Physics at FAU considers accelerator miniaturisation to be a technical revolution analogous to the development of computers, which went from occupying entire rooms to fitting on people’s wrists. ‘This approach will hopefully enable us to make this innovative particle acceleration technique usable in a range of research areas and fields of application such as materials science, biology and medicine; one example might be particle therapies for cancer patients.’

In 2015, the FAU researchers teamed up with scientists from Stanford University and eight other international partner institutions in the Accelerator on a Chip International Program (ACHIP). The Gordon and Betty Moore Foundation has generously provided five years’ funding to the project; of the total grant of 13.5 million dollars (approximately 12.5 million euro), 2.44 million dollars (approximately 2.26 million euro) went to FAU.

The research team’s findings have now been published in the leading scientific journal Nature Physics (doi: 10.1038 / nphys4282).

Further information:
Prof. Dr. Peter Hommelhoff
Phone: +49 9131 8527090

Dr. Susanne Langer | idw - Informationsdienst Wissenschaft
Further information:

More articles from Physics and Astronomy:

nachricht Sharpening the X-ray view of the nanocosm
23.03.2018 | Changchun Institute of Optics, Fine Mechanics and Physics

nachricht Drug or duplicate?
23.03.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF

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: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>