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

U.S. Air Force Research Lab Taps IBM to Build Brain-Inspired AI Supercomputing System: Equal to 64 million neurons, new neurosynaptic supercomputing system will power complex AI tasks at unprecedented speed and energy efficiency June 23rd, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Physics

In atomic propellers, quantum phenomena can mimic everyday physics June 1st, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Possible Futures

U.S. Air Force Research Lab Taps IBM to Build Brain-Inspired AI Supercomputing System: Equal to 64 million neurons, new neurosynaptic supercomputing system will power complex AI tasks at unprecedented speed and energy efficiency June 23rd, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Announcements

U.S. Air Force Research Lab Taps IBM to Build Brain-Inspired AI Supercomputing System: Equal to 64 million neurons, new neurosynaptic supercomputing system will power complex AI tasks at unprecedented speed and energy efficiency June 23rd, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Tools

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Oxford Instruments congratulates Lancaster University for inaugurating the IsoLab, built for studying quantum systems June 20th, 2017

Changing the color of laser light on the femtosecond time scale: How BiCoO3 achieves second harmonic generation June 14th, 2017

Leti Announces Two New Tools for Improving Transportation Comfort, Safety and Efficiency: Wearable Device Measures Stress Responses for Travelers, Pilots and Truck Drivers, While Smartphone App Provides Transit Agencies Broad Data on Transport Modes June 13th, 2017

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

U.S. Air Force Research Lab Taps IBM to Build Brain-Inspired AI Supercomputing System: Equal to 64 million neurons, new neurosynaptic supercomputing system will power complex AI tasks at unprecedented speed and energy efficiency June 23rd, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Smart materials used in ultrasound behave similar to water, Penn chemists report June 16th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Quantum Dots/Rods

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

The brighter side of twisted polymers: Conjugated polymers designed with a twist produce tiny, brightly fluorescent particles with broad applications May 16th, 2017

Nanoparticles open new window for biological imaging: “Quantum dots” that emit infrared light enable highly detailed images of internal body structures April 10th, 2017

Particle Works creates range of high performance quantum dots February 23rd, 2017

Quantum nanoscience

Oxford Instruments congratulates Lancaster University for inaugurating the IsoLab, built for studying quantum systems June 20th, 2017

In atomic propellers, quantum phenomena can mimic everyday physics June 1st, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

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