Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Laser light produces complex nanostructures

28.05.2008
Researchers at Chalmers University of Technology in Sweden have reported that a single laser pulse can create complex, ordered nanostructure systems.

This previously unobserved phenomenon has just beeen described in an article in the scientific journal Nature Photonics.

- We have discovered a method for controlling the pattern into which the nanoparticles organize themselves, says physicist Dinko Chakarov, one of the authors of the article.

The complex nanostructures that are created may find applications in fibre optics, optical sensors and advanced light emitting diodes and lasers.

The researchers started with a layer of disordered nanoparticles of gold or silver on a membrane of nanometre thickness. The patterning is a consequence of several transformations of the light, which finally results in partial melting and moving of the nanoparticles.

First, the light is caught by the particles, resulting in resonant swinging back and forth of the particle electrons (so called localized plasmon resonances). This specific excitation gives rise to scattering and coupling of electromagnetic energy into trapped, waveguided modes of the thin membrane. The edges of the membrane cause a standing wave pattern to be formed.

The end result is hot and cold zones of a specific periodicity on the membrane surface, and if the laser light energy is high enough, the field energy in the hot zones is high enough to melt and move the gold particles. All of this occurs within a few nanoseconds or even faster, and the resulting patterns have dimensions that can be both smaller and larger than the laser wavelength.

The results demonstrate that complex nanostructured systems can be fabricated and manipulated by a single laser pulse. In addition, the study shows in a very concrete manner that assemblies of optically active nanoparticles can be used to trap light in a waveguide (membrane or fibre) with nanometer dimensions.

The researchers have shown that the pattern can be controlled by varying several parameters: the laser light angle, wavelength and polarization, as well as the membrane thickness and the type of particles on the membrane.

The discovery contributes to the understanding of the fundamental interaction between light and matter. The study also shows how plasmon resonance can be used to enhance light absorption, which may be of use for the production of better solar cells, see previous article: "Energetic nanoparticles swing sunlight into electricity"

Further information:
Dinko Chakarov, Department of Applied Physics, Chalmers University of Technology
Tel:+46 (0)31 772 3375
dinko.chakarov@fy.chalmers.se
Pressofficer Sofie Hebrand, +46 736-79 35 90; sofie.hebrand@chalmers.se

Sofie Hebrand | idw
Further information:
http://publications.lib.chalmers.se/cpl/record/index.xsql?pubid=67239
http://www.nature.com/nphoton/journal/vaop/ncurrent/abs/nphoton.2008.80.html

More articles from Physics and Astronomy:

nachricht Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>