Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum communications bend to our needs

27.09.2017

By changing the wavelengths of entangled photons to those used in telecommunications, researchers see quantum technology take a major leap forward

The potential for photon entanglement in quantum computing and communications has been known for decades. One of the issues impeding its immediate application is the fact that many photon entanglement platforms do not operate within the range used by most forms of telecommunication.


This is a schematic of the emission of entangled photon pairs from a quantum dot.

Credit: Sascha Kolatschek

An international team of researchers has started to unravel the mysteries of entangled photons, demonstrating a new nanoscale technique that uses semiconductor quantum dots to bend photons to the wavelengths used by today's popular C-band standards. They report their work this week in Applied Physics Letters, from AIP Publishing.

"We have demonstrated the emission of polarization-entangled photons from a quantum dot at 1550 nanometers for the first time ever," said Simone Luca Portalupi, one of the work's authors and a senior scientist at the Institute of Semiconductor Optics and Functional Interfaces at the University of Stuttgart. "We are now on the wavelength that can actually carry quantum communication over long distances with existing telecommunication technology."

The researchers used quantum dots created from an indium arsenide and gallium arsenide platform, producing pure single photons and entangled photons. Unlike parametric down-conversion techniques, quantum dots allow for photons to be emitted only one at a time and on demand, crucial properties for quantum computing. A distributed Bragg reflector, which is made from multiple layered materials and reflects over a wide spectrum, then directed the photons to a microscope objective, allowing them to be collected and measured.

Researchers and industry leaders have found that the C-band -- a specific range of infrared wavelengths -- has become an electromagnetic sweet spot in telecommunications. Photons traveling through both optical fibers and the atmosphere within this range experience significantly less absorption, making them perfect for relaying signals across long distances.

"The telecom C-band window has the absolute minimum absorption we can achieve for signal transmission," said Fabian Olbrich, another of the paper's authors. "As scientists have made discoveries, industry has improved technology, which has let scientists make more discoveries, and so now we have a standard that works very well and has low dispersion."

Most entangled photons originating from quantum dots, however, operate near 900 nanometers, closer to wavelengths we can see with the naked eye.

The researchers were impressed by the quality of the signal, Olbrich said. Other efforts to shift the emission wavelength of polarization-entangled photons of quantum dots toward the C-band tended to increase the exciton fine-structure splitting (FSS), a quantity that should be close to zero for entanglement generation. Olbrich's team reports their experiment experienced less than one-fifth as much FSS as other studies in the literature.

"The chance to find a quantum dot that is able to emit polarization-entangled photons with high fidelity is quite high for our specific study," Olbrich said.

With each successful experiment, the quantum communications community is seeing its field bend toward greater applicability in today's telecommunications industry. Researchers hope that one day, entangled photons will impact cryptography and secure satellite communications.

"The hard part now is to combine all the advantages of the system and fulfill prerequisites such as high photon indistinguishability, high temperature operation, increased photon flux and out coupling efficiency that would make them work," Olbrich said.

###

The article, "Polarization-entangled photons from an InGaAs-based quantum dot emitting in the telecom C-band," is authored by Fabian Olbrich, Jonatan Höschele, Markus Müller, Jan Kettler, Simone Luca Portalupi, Matthias Paul, Michael Jetter and Peter Michler. The article will appear in Applied Physics Letters Sept. 26, 2017 (DOI: 10.1063/1.4994145). After that date, it can be accessed at http://aip.scitation.org/doi/full/10.1063/1.4994145.

ABOUT THE JOURNAL

Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See http://apl.aip.org.

Media Contact

Julia Majors
media@aip.org
301-209-3090

 @AIPPhysicsNews

http://www.aip.org 

Julia Majors | EurekAlert!

More articles from Information Technology:

nachricht Three components on one chip
06.12.2018 | Universität Stuttgart

nachricht New quantum materials could take computing devices beyond the semiconductor era
04.12.2018 | University of California - Berkeley

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

Inaugural "Virtual World Tour" scheduled for december

28.11.2018 | Event News

 
Latest News

A new molecular player involved in T cell activation

07.12.2018 | Life Sciences

High-temperature electronics? That's hot

07.12.2018 | Materials Sciences

Supercomputers without waste heat

07.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>