Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

On the crest of the wave: Electronics on a time scale shorter than a cycle of light

30.07.2015

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and engineers all over the world have racked their brains about one central question:


An intense lightwave drives ultrafast electronic motion in a bulk crystal. A novel quantum interference creates free electrons and causes the emission of ultrashort high-harmonic light bursts.

Image: B. Baxley (parttowhole.com)

Is there a fundamental limit for the speed of electronics? Indeed, all electronic circuits rely on charge motion controlled by electric fields. Future high-speed electronics would, therefore, benefit immensely from bias fields that switch faster than state-of-the-art electronic clocks. The solution to this challenge may be surprisingly straightforward: One could try to employ the fastest alternating electric field available in nature – a light wave.

The team of researchers from Germany has now directly observed the electrons’ motion in a semiconductor driven by a strong light pulse in the terahertz spectral region. The pioneering experiment carried out in Rupert Huber’s group at the University of Regensburg enabled the first simultaneous clocking measurement of extremely broadband radiation sent out by the accelerated electrons, so-called high-order harmonics, and the driving light wave.

It turns out that the harmonics are emitted in ultrashort light bursts which have now been characterized with a temporal resolution of approximately one femtosecond – the millionth of a billionth part of a second. In combination with numerical simulations performed in the groups of Mackillo Kira and Stephan W. Koch at the University of Marburg, this study provides unprecedented insights into the quantum world of a solid.

The results shed light onto a surprising behavior of the crystal electrons: During an extremely short timespan after excitation, the strong light field drives an electron simultaneously along multiple paths instead of one only. This strange scenario is possible in the quantum world where particles can behave like waves.

As an indisputable quantum wave aspect, the electrons were shown to interfere constructively (destructively) only at the positive (negative) crests of the driving field, massively reshaping the temporal emission of the harmonics. While such quantum effects are often fragile and usually become observable only in extremely gentle fields the newly discovered phenomenon is qualitatively different because it is robust, producing pronounced interference contrast especially for extremely strong driving fields.

The breakthrough reveals the temporal structure of high-harmonics from a solid for the first time and thus helps the development of new sources of ever shorter light pulses. Moreover, this discovery opens new perspectives for modern high-speed electronics and sets an important milestone on the way towards light-wave-driven electronics.

Original publication:
M. Hohenleutner, F. Langer, O. Schubert, M. Knorr, U. Huttner, S. W. Koch, M.Kira und R. Huber, Real-time observation of interfering crystal electrons in high-harmonic generation, Nature (2015), DOI: 10.1038/nature14652
Publication: http://dx.doi.org/10.1038/nature14652

Contact:
Prof. Dr. Rupert Huber
Universität Regensburg
Universitätsstraße 31
93053 Regensburg
Germany
E-Mail: rupert.huber@physik.uni-regensburg.de

Prof. Dr. Mackillo Kira
Philipps-Universität Marburg
Renthof 5
35032 Marburg
Germany
E-Mail: mackillo.kira@physik.uni-marburg.de

Alexander Schlaak | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-regensburg.de/

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>