Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



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

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Shedding light on perovskite hydrides using a new deposition technique: Researchers develop a methodology to grow single-crystal perovskite hydrides, enabling accurate hydride conductivity measurements May 17th, 2024

Physics

Finding quantum order in chaos May 17th, 2024

International research team uses wavefunction matching to solve quantum many-body problems: New approach makes calculations with realistic interactions possible May 17th, 2024

Possible Futures

Advances in priming B cell immunity against HIV pave the way to future HIV vaccines, shows quartet of new studies May 17th, 2024

International research team uses wavefunction matching to solve quantum many-body problems: New approach makes calculations with realistic interactions possible May 17th, 2024

Aston University researcher receives £1 million grant to revolutionize miniature optical devices May 17th, 2024

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Announcements

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Tools

First direct imaging of small noble gas clusters at room temperature: Novel opportunities in quantum technology and condensed matter physics opened by noble gas atoms confined between graphene layers January 12th, 2024

New laser setup probes metamaterial structures with ultrafast pulses: The technique could speed up the development of acoustic lenses, impact-resistant films, and other futuristic materials November 17th, 2023

Ferroelectrically modulate the Fermi level of graphene oxide to enhance SERS response November 3rd, 2023

The USTC realizes In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors November 3rd, 2023

Homeland Security

The picture of health: Virginia Tech researchers enhance bioimaging and sensing with quantum photonics June 30th, 2023

Sensors developed at URI can identify threats at the molecular level: More sensitive than a dog's nose and the sensors don't get tired May 21st, 2021

UCF researchers generate attosecond light from industrial laser: The ultrafast measurement of the motion of electrons inside atoms, molecules and solids at their natural time scale is known as attosecond science and could have important implications in power generation, chemical- August 25th, 2020

Highly sensitive dopamine detector uses 2D materials August 7th, 2020

Military

NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

New chip opens door to AI computing at light speed February 16th, 2024

Quantum Dots/Rods

A new kind of magnetism November 17th, 2023

IOP Publishing celebrates World Quantum Day with the announcement of a special quantum collection and the winners of two prestigious quantum awards April 14th, 2023

Qubits on strong stimulants: Researchers find ways to improve the storage time of quantum information in a spin rich material January 27th, 2023

NIST’s grid of quantum islands could reveal secrets for powerful technologies November 18th, 2022

Quantum nanoscience

What is "time" for quantum particles? Publication by TU Darmstadt researchers in renowned journal "Science Advances" May 17th, 2024

Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024

Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024

Bridging light and electrons January 12th, 2024

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project