Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Photons open the gateway for quantum networks

23.10.2015

There is tremendous potential for new information technology based on light (photons). Photons (light particles) are very well suited for carrying information and quantum technology based on photons -- called quantum photonics, will be able to hold much more information than current computer technology.

But in order to create a network with photons, you need a photon contact, a kind of transistor that can control the transport of photons in a circuit. Researchers at the Niels Bohr Institute in collaboration with researchers from the Korea Institute of Science and Technology have managed to create such a contact. The results are published in the scientific journal Nature Communications.


Alisa Javadi, a postdoc in the Quantum Photonic research group, has worked with the experiments in the laboratory at the Niels Bohr Institute, University of Copenhagen.

Credit: Ola Jakup Joensen, Niels Bohr Institute, University of Copenhagen

Quantum information can be sent optically, that is to say, using light, and the signal is comprised of photons, which is the smallest component (a quantum) of a light pulse. Quantum information is located in whichever path the photon is sent along -- it can, for example, be sent to the right or to the left on a semi-transparent mirror.

It can be compared to the use of bits made up of 0s and 1s in the world of conventional computers. But a quantum bit is more than a classical bit, since it is both a 0 and a 1 at the same time and it cannot be read without it being detected, as it is only a single photon. In addition, quantum technology can be used to store far more information than conventional computer technology, so the technology has much greater potential for future information technology.

Controlling the light

Light normally spreads in all directions. But in order to develop quantum technology based on light, you need to be able to control light down to the individual photons. Researchers in the Quantum Photonic research group at the Niels Bohr Institute are working on this and to do so, they use an optical chip embedded with a so-called quantum dot.

The optical chip is made up of an extremely small photonic crystal, which is 10 microns across (1 micron is a thousandth of a millimetre) and has a thickness of 160 nanometers (1 nanometer is a thousandth of a micron). Embedded in the middle of the chip is a so-called quantum dot, which is comprised of a collection of atoms.

"We have developed the photonic chip so that the quantum dot emits a single photon at a time and we can control the photon's direction. Our big new achievement is that we can use the quantum dot as a contact for the photons -- a kind of transistor. It is an important component for creating a complex network of photons," explains Peter Lodahl, professor and head of the Quantum Photonic research group at the Niels Bohr Institute at the University of Copenhagen.

'Gateway' for photons

The experiments are carried out in the research group's laboratories, which located in the basement of the Niels Bohr Institute so that there are no tremors from the road or disruptive ambient light.

They use a laser to produce the photons in the experiment. If the laser is fully dimmed, a single photon is released. If the intensity is increased, there is a greater chance of 2 or more photons at the same time. The number of photons is important for the result.

"If we send a single photon into the quantum dot, it will be thrown back -- the gateway is closed. But if we send two photons, the situation changes fundamentally -- the gateway is opened and the two photons become entangled and are sent onwards," explains Alisa Javadi, who is a postdoc in the research group and has worked with the experiments in the laboratory at the Niels Bohr Institute.

So the quantum dot works as a photon contact and this is an important component when you want to build complex quantum photonic circuits on a large scale.

###

Contact:
Peter Lodahl Professor
45-2056-5303
lodahl@nbi.ku.dk
Head of the Quantum Photonic research group at the Niels Bohr Institute at the University of Copenhagen

Søren Stobbe
45-3532-5216
stobbe@nbi.ku.dk
Associate Professor in the Quantum Photonic research group at the Niels Bohr Institute at the University of Copenhagen.

Alisa Javadi,
45-6065-6769
javadi@nbi.ku.dk
Postdoc in Quantum Photonic research group at the Niels Bohr Institute at the University of Copenhagen.

Media Contact

Gertie Skaarup
skaarup@nbi.dk
45-28-75-06-20

http://www.nbi.ku.dk/english/press_and_media/ 

Gertie Skaarup | EurekAlert!

More articles from Physics and Astronomy:

nachricht Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>