Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Metamaterials shake up electrons

29.09.2008
New man-made materials could produce unique chaotic motion in electron beams

A team at the RIKEN Advanced Science Institute in Wako has predicted that man-made structures called metamaterials could produce instabilities in electron beams (1). The effect could provide new methods for generating and amplifying optical signals.

Metamaterials are often known as left-handed media (LHM) because they break the right-hand rule of electromagnetism. This means that the ‘envelope’ of a wave—created by changes in wave height—in LHM can move in the opposite direction to the wave’s overall motion. This is expected to produce phenomena similar to backward wave oscillators, which are common sources of microwave radiation.

“Any system that contains two oppositely directed fluxes of information can be unstable if the coupling between the information carriers (waves and electrons in our case) is strong enough,” explains RIKEN scientist Yuriy Bliokh, also at Technion-Israel Institute of Technology in Haifa.

The coupling between carriers in LHM is provided by Cherenkov radiation—a type of radiation emitted when a charged particle passes through an insulator at a speed faster than the speed of light in the insulator. It is responsible for the blue glow in nuclear reactors, and propagates from a particle beam just like the wake from a moving ship.

In LHM, Cherenkov radiation moves backwards, providing strong feedback for particles moving behind. In particular, two electron beams side-by-side could excite each other via their Cherenkov radiation, producing unstable, chaotic motion in the beams.

To investigate these effects, Bliokh and RIKEN co-workers Sergey Savel’ev, also at Loughborough University, UK, and Franco Nori, also at the University of Michigan, USA, developed a model which solves the equations of motion for two electron beams passing through LHM, and calculates the total electric field generated. "Small perturbations in the beam density were introduced to represent fluctuations that can occur in the real world," says Savel'ev.

The small perturbations developed into large instabilities, causing the beam to excite itself. "The behavior resembles beam instabilities that have been discovered in both plasma physics and microwave electronics," says Nori, and could have several applications if a suitable LHM can be realized in the laboratory.

“From my point of view, the most interesting applications would be in the short-wavelength (infrared, visible light) range, because there are already so many devices in the microwave frequency band,” says Bliokh. “This effect could provide tunable sources of regular or stochastic radiation. Also, when the beam current is low, the instability is not developed and the system could be used as an amplifier.”

1. Bliokh, Y.P., Savel’ev, S. & Nori, F. Electron-beam instability in left-handed media. Physical Review Letters 100, 244803 (2008).

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/539/
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>