Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Nano-towers fire off single photons

Abstract:
Würzburg physicists are global leaders in the creation of sophisticated nanostructures. The fruits of their research could make tap-proof data transmission a possibility in the future.

Nano-towers fire off single photons

Würzburg | Posted on November 26th, 2009

At the heart of the concept are tiny towers, made from semiconducting material, at the University of Würzburg's Department of Applied Physics. They are around ten micrometers in height, with a diameter of just one to two micrometers (a human hair is roughly a hundred times thicker).

Contained inside the towers are special structures capable of emitting light: these are known as quantum dots, and their electronic and optical properties can be customized during production. Quantum dots, in the same way as single atoms, possess precisely defined energy states. This enables them to send out photons (light particles) with an exact amount of energy.

Single photons can be generated

What is special about the Würzburg quantum dot towers is that "with them it is possible to 'fire off' single photons in a targeted fashion. It is structural elements like these that are needed for the tap-proof transmission of data in the field of quantum cryptography," explains Würzburg physicist Stephan Reitzenstein.

However, to date, the production of single photons in these structures has only been achieved with temperatures well below minus 100 degrees Celsius. So, there are still hurdles to overcome before the concept can be routinely applied.

Publication in Nature Photonics

Thanks to the tiny towers developed in Würzburg, there are now new insights into quantum dots. Physicists on Professor Peter Michler's team (Institute of Semiconductor Optics and Functional Interfaces of the University of Stuttgart) have published these jointly with their Würzburg colleagues in the journal Nature Photonics.

Those involved in the publication from Würzburg's Department of Applied Physics were Stephan Reitzenstein, Andreas Löffler, Sven Höfling, and Professor Alfred Forchel. The Stuttgart team included Serkan Ates, Sven M. Ulrich, Ata Ulhaq, and Professor Peter Michler.

New tool for analyzing quantum dots

The Stuttgart physicists studied the Würzburg nano-towers as part of a venture sponsored by the German Research Foundation (DFG). "The towers serve as a new tool for analyzing the properties of quantum dots in a way never seen before," explains Reitzenstein.

The Stuttgart team discovered an unexpected effect, known as non-resonant coupling. This suggests strong light-matter interactions in such solid-state systems. According to Peter Michler, "this will have major repercussions on the design and functionality of future quantum emitters that are based on quantum dots."

Structure of the Würzburg towers

The new insights were made possible by the special structure and highly optimized production of the towers. The quality of the towers realized at the University of Würzburg is outstanding by global comparison.

The tiny structures consist of a sophisticated sequence of layers made from the semiconductors aluminum arsenide and gallium arsenide. "Their special structure makes them into high-quality optical resonators, which confine single photons on a light wavelength scale in all three spatial dimensions," says Stephan Reitzenstein.

Embedded in the center of the towers are some 100 quantum dots made from the semiconducting material indium gallium arsenide. Reitzenstein: "Using special spectroscopic procedures, however, a single quantum dot can purposefully be brought into resonance with the optical mode of a tower in order to conduct fundamental physics experiments on the interaction between light and matter."

Non-resonant dot-cavity coupling and its potential for resonant single-quantum-dot spectroscopy, S. Ates, S. M. Ulrich, A. Ulhaq, S. Reitzenstein, A. Löffler, S. Hoöfling, A. Forchel, and P. Michler, Nature Photonics, published online on Nov. 22, 2009, doi:10.1038/nphoton.2009.215

####

About University of Würzburg
The roots of Julius-Maximilians University at Würzburg reach back as far as 1402 AD. In that era, it was the sixth institution of higher learning to be founded in the German-speaking regions of Europe, after the Universities of Prague, Vienna, Heidelberg, Cologne, and Erfurt.

For more information, please click here

Contacts:
Dr. Stephan Reitzenstein
University of Würzburg
phone +49 931 31-85116

Dr. Sven M. Ulrich
University of Stuttgart
phone +49 711 685-65226

Copyright © University of Würzburg

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Nanoscale view of energy storage January 16th, 2017

Seeing the quantum future... literally: What if big data could help you see the future and prevent your mobile phone from breaking before it happened? January 16th, 2017

NUS researchers achieve major breakthrough in flexible electronics: New classes of printable electrically conducting polymer materials make better electrodes for plastic electronics and advanced semiconductor devices January 14th, 2017

Manchester scientists tie the tightest knot ever achieved January 13th, 2017

Nanoscale Modifications can be used to Engineer Electrical Contacts for Nanodevices January 13th, 2017

Physics

Seeing the quantum future... literally: What if big data could help you see the future and prevent your mobile phone from breaking before it happened? January 16th, 2017

Possible Futures

Nanoscale view of energy storage January 16th, 2017

Seeing the quantum future... literally: What if big data could help you see the future and prevent your mobile phone from breaking before it happened? January 16th, 2017

NUS researchers achieve major breakthrough in flexible electronics: New classes of printable electrically conducting polymer materials make better electrodes for plastic electronics and advanced semiconductor devices January 14th, 2017

Nanoscale Modifications can be used to Engineer Electrical Contacts for Nanodevices January 13th, 2017

Announcements

Nanoscale view of energy storage January 16th, 2017

Seeing the quantum future... literally: What if big data could help you see the future and prevent your mobile phone from breaking before it happened? January 16th, 2017

NUS researchers achieve major breakthrough in flexible electronics: New classes of printable electrically conducting polymer materials make better electrodes for plastic electronics and advanced semiconductor devices January 14th, 2017

Nanoscale Modifications can be used to Engineer Electrical Contacts for Nanodevices January 13th, 2017

Tools

Distinguishing truth under the surface: electrostatic or mechanic December 31st, 2016

Nanomechanics Inc. Continues Growth in Revenue and Market Penetration: Leading nanoindentation company reports continued growth in revenues and distribution channels on national and international scales December 27th, 2016

Nanometrics to Present at the 19th Annual Needham Growth Conference December 22nd, 2016

Safe and inexpensive hydrogen production as a future energy source: Osaka University researchers develop efficient 'green' hydrogen production system that operates at room temperature in air December 21st, 2016

Homeland Security

Nanosensors on the alert for terrorist threats: Scientists interested in the prospects of gas sensors based on binary metal oxide nanocomposites November 5th, 2016

Nanobionic spinach plants can detect explosives: After sensing dangerous chemicals, the carbon-nanotube-enhanced plants send an alert November 2nd, 2016

Notre Dame researchers find transition point in semiconductor nanomaterials September 6th, 2016

Down to the wire: ONR researchers and new bacteria August 18th, 2016

Military

Nanoscale view of energy storage January 16th, 2017

Manchester scientists tie the tightest knot ever achieved January 13th, 2017

Deciphering the beetle exoskeleton with nanomechanics: Understanding exoskeletons could lead to new, improved artificial materials January 12th, 2017

New laser based on unusual physics phenomenon could improve telecommunications, computing January 12th, 2017

Quantum Dots/Rods

Carbon dots dash toward 'green' recycling role: Rice scientists, colleagues use doped graphene quantum dots to reduce carbon dioxide to fuel December 18th, 2016

Two electrons go on a quantum walk and end up in a qudit: Russian scientists find a way to reliably connect quantum elements December 13th, 2016

Trickling electrons: Close to absolute zero, the particles exhibit their quantum nature November 10th, 2016

Notre Dame researchers find transition point in semiconductor nanomaterials September 6th, 2016

Quantum nanoscience

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Quantum simulation technique yields topological soliton state in SSH model January 3rd, 2017

Diamonds are technologists' best friends: Researchers from the Lomonosov Moscow State University have grown needle- and thread-like diamonds and studied their useful properties December 30th, 2016

Two electrons go on a quantum walk and end up in a qudit: Russian scientists find a way to reliably connect quantum elements December 13th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project