Research & Development World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • Educational Assets
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE

Making Lasers with Graphene

By R&D Editors | November 24, 2014

Free-Electron Laser at ELBE. Photo: HZDR/Frank BierstedtScientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have studied the dynamics of electrons from the “wonder material” graphene in a magnetic field for the first time. This led to the discovery of a seemingly paradoxical phenomenon in the material. Its understanding could make a new type of laser possible in the future. Together with researchers from Berlin, France, the Czech Republic, and the United States, the scientists precisely described their observations in a model and have now published their findings in the scientific journal Nature Physics.

Graphene is considered a “wonder material”: its breaking strength is higher than steel and it conducts electricity and heat more effectively than copper. As a two-dimensional structure consisting of only a single layer of carbon atoms, it is also flexible, nearly transparent and approximately one million times thinner than a sheet of paper. Furthermore, shortly after its discovery ten years ago, scientists recognized that the energy states of graphene in a magnetic field – known as Landau levels – behave differently than those of semiconductors.

“Many fascinating effects have been discovered with graphene in magnetic fields, but the dynamics of electrons have never been studied in such a system until now,” explains physicist Dr. Stephan Winnerl from HZDR.

The HZDR researchers exposed the graphene to a four-Tesla magnetic field – forty times stronger than a horseshoe magnet. As a result, the electrons in graphene occupy only certain energy states. The negatively charged particles were virtually forced on tracks. These energy levels were then examined with free-electron laser light pulses at the HZDR.

“The laser pulse excites the electrons into a certain Landau level. A temporally delayed pulse then probes how the system evolves,” explains Martin Mittendorff, doctoral candidate at the HZDR and first author of the paper.

The result of the experiments has astonished the researchers. This particular energy level, into which new electrons were pumped using the laser, gradually emptied. Winnerl illustrates this paradoxical effect using an everyday example: “Imagine a librarian sorting books on a bookshelf with three shelves. She places one book at a time from the lower shelf onto the middle shelf. Her son is simultaneously ‘helping’ by taking two books from the middle shelf, placing one of them on the top shelf, the other on the bottom. The son is very eager and now the number of books on the middle shelf decreases even though this is precisely the shelf his mother wishes to fill.”

Because there were neither experiments nor theories regarding such dynamics before, the Dresden physicists initially had difficulty interpreting the signals correctly. After a number of attempts, however, they found an explanation: collisions between electrons cause this unusual rearrangement. “This effect has long been known as Auger scattering, but no one expected it would be so strong and would cause an energy level to become depleted,” explains Winnerl.

This new discovery could be used in the future for developing a laser that can produce light with arbitrarily adjustable wavelengths in the infrared and terahertz ranges. “Such a Landau-level laser was long considered impossible, but now with graphene this semiconductor physicists’ dream could become a reality,” says Winnerl enthusiastically.

After the fundamental model used in the experiments had worked satisfactorily, the precise theoretical work followed, which was carried out at the Technical University Berlin. Berlin scientists Ermin Malic and Andreas Knorr confirmed, using complex calculations, the Dresden group’s assumptions and provided detailed insights into the underlying mechanisms. The HZDR researchers additionally cooperated with the French High Magnetic Field Laboratory in Grenoble (Laboratoire National des Champs Magnétiques Intenses – LNCMI), the Charles University Prague and the Georgia Institute of Technology in Atlanta (USA).

The research has been funded by the German research association DFG (Deutsche Forschungsgemeinschaft) within the program “Graphene”.

Release Date: November 24, 2014
Source: Helmholtz-Zentrum Dresden-Rossendorf 

Related Articles Read More >

Illustration of ultracold atoms (gold) flowing frictionlessly along a laser boundary (green), representing the quantum phenomenon of edge states.
MIT physicists directly observe frictionless ‘edge state’ flow in ultracold atoms, offering a glimpse of super-efficient electronics
NTT Research scientist in cleanroom suit working on advanced photonic equipment
NTT Research bets light-based computing can tackles AI’s energy crisis
Scientists claim to generate world’s strongest terahertz radiation
SLAC fires up the world’s most powerful X-ray laser: LCLS-II ushers in a new era of science
rd newsletter
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, trends, and strategies in Research & Development.
RD 25 Power Index

R&D World Digital Issues

Fall 2024 issue

Browse the most current issue of R&D World and back issues in an easy to use high quality format. Clip, share and download with the leading R&D magazine today.

Research & Development World
  • Subscribe to R&D World Magazine
  • Enews Sign Up
  • Contact Us
  • About Us
  • Drug Discovery & Development
  • Pharmaceutical Processing
  • Global Funding Forecast

Copyright © 2025 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search R&D World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • Educational Assets
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE