Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physicists develop an innovative light source

26.01.2012
Tiny components with the ability to emit single particles of light are important for various technological innovations. Physicists of the Universities of Würzburg, Stuttgart and Ulm have made significant progress in the fabrication of such structures.

Why are researchers interested in light sources that are able to emit single particles of light? "Such light sources are a basic requirement for the development of new encryption technologies," explains Professor Jens Pflaum at the Institute of Physics of the University of Würzburg.


The innovative component with which single photons can be produced at room temperature (red arrow) is schematically represented in the diagram below and shown in action in the picture on top. Electric current passes through the circular contacts, stimulating the underlying color molecules to light up. The optically active area of the component is about two millimeters in diameter. Photo: Benedikt Stender


Chemical structure of the iridium-based molecule used by the scientists to produce single photons. Institute of Physics, University of Würzburg

Suitably equipped components would be able to ensure that data can no longer be "fished for" during transmission without such process being noticed. These components might be used, for instance, to increase the security of online payment systems – since any data manipulation would be immediately detected and the relevant counter measures could be directly implemented. This cannot be achieved with conventional light sources, such as lasers, because these always emit large quantities of identical light particles or photons as they are referred to by physicists.

Advantages of the innovative light source

An innovative component that emits single photons has now been introduced by Professor Pflaum and his cooperation partners from Stuttgart and Ulm in the prestigious journal "Nature Communications".
The innovative light source has more than just one advantage: It consists of standard materials for organic light-emitting diodes, is pretty easy to manufacture and can be electrically controlled. What's most important: It works at room temperature. So far, any comparable optical components manufactured from semiconductor materials, such as gallium arsenide, are only functional at temperatures far below the freezing point.

Single color molecules in a matrix

What's the design of the new component? "It's quite similar to the pixel of a display, familiar to everybody with a mobile phone," explains Professor Pflaum: An electrically conductive layer is applied to a substrate – in our case represented by a glass plate. Next, an organic plastic matrix, in which the individual color molecules are embedded, is added onto this layer. The matrix is then fitted with electrical contacts. If these are connected to a battery, a flow of electrical current to the color molecules is induced, stimulating them to continually fire single photons. This has been demonstrated by the physicists with photon correlation measurements.

Three crucial tricks used

Three tricks were crucial for the achievement. Number one: "We selected the right color molecules," says Maximilian Nothaft of the University of Stuttgart. The molecules have chemical structures in which three organic complexes are grouped around one central iridium atom.

Trick number two: The physicists provided for a proper distribution of the color molecules within the matrix. Too densely packed molecules would have interacted, no longer emitting single independent photons.

Trick number three: "The interface between the electrical contacts and the matrix has been well designed by us," explains Professor Jörg Wrachtrup of the University of Stuttgart. This is important for enabling the required electrons, the carriers of the electric charge, to be injected into the polymer matrix in the first place. In this case, the scientists were successful with a contact comprised of an aluminum / barium double layer.

Glimpse into the future

What are the physicists going to do next? "We shall try to deposit the matrix with the color molecules and the electrical contacts onto various materials so that we can use flexible substrates, such as plastic films," says Professor Pflaum. This can be done with a device that works like an ink jet printer, which is a standard technology that has been used in laboratories for years. The advantage of this is: The light sources can be even better positioned on a surface.

Studies funded by DFG

This success has been achieved under the umbrella of Research Group 730 ("Positioning of single nanostructures – Single quantum devices"), which is funded by the German Research Foundation (DFG). The spokesperson of the group is Professor Peter Michler of the University of Stuttgart.

"Electrically driven photon antibunching from a single molecule at room temperature", Maximilian Nothaft, Steffen Höhla, Fedor Jelezko, Norbert Frühauf, Jens Pflaum & Jörg Wrachtrup, Nature Communications 3 (628), 17 January 2012, doi:10.1038/ncomms1637

Contact

Prof. Dr. Jens Pflaum, Institute of Physics of the University of Würzburg, T +49 (0)931 31-83118, jpflaum@physik.uni-wuerzburg.de

Maximilian Nothaft and Prof. Dr. Jörg Wrachtrup, 3rd Institute of Physics of the University of Stuttgart, T +49 (0)711 685-65273, m.nothaft@physik.uni-stuttgart.de

Robert Emmerich | Julius-Maximilians-Universität W
Further information:
http://www.uni-wuerzburg.de

More articles from Physics and Astronomy:

nachricht Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside

nachricht New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory

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

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>