Featured Research

from universities, journals, and other organizations

Quantum cryptography? Physicists move closer to efficient single-photon sources

Date:
March 17, 2011
Source:
American Institute of Physics
Summary:
A team of physicists has taken a giant step toward realizing efficient single-photon sources, which are expected to enable much-coveted completely secure optical communications, also known as "quantum cryptography."

A team of physicists in the United Kingdom has taken a giant step toward realizing efficient single-photon sources, which are expected to enable much-coveted completely secure optical communications, also known as "quantum cryptography."

Related Articles


The team presents its findings in Applied Physics Letters, a journal published by the American Institute of Physics.

Fluorescent "defect centers" in diamond act like atomic-scale light sources and are trapped in a transparent material that's large enough to be picked up manually. They don't need to be kept at super cold cryogenic temperatures or trapped in large electromagnetic fields to be stable -- unlike quantum dots or trapped atoms.

This makes them strong contenders for use as sources of single photons (the quantum light particle) in provably secure quantum cryptography schemes, explains J. P. Hadden, a Ph.D. candidate in the Centre for Quantum Photonics, Department of Electrical and Electronic Engineering & H. H. Wills Physics Laboratory at the University of Bristol.

"Defect centers could also be used as building blocks for 'solid-state quantum computers,' which would use quantum effects to solve problems that are not efficiently solvable with current computer technology," Hadden says.

To fulfill the potential of diamond defect centers, it's essential that the light be collected efficiently from the diamond material. But this collection efficiency is dramatically reduced by reflection and refraction of light passing through the diamond-air interface.

"We managed to show an improvement in the brightness of these defect centers of up to ten times by etching hemispherical 'solid immersion lenses' into the diamond," notes Hadden. "This is an important result, showing how nanofabrication techniques can complement and enhance quantum technologies, and opens the door to diamond-defect-center-based implementations of quantum cryptography and quantum computation."

More recently, Hadden and colleagues developed a technique that allows them to reliably etch these structures over previously characterized defect centers to a precision of about 100 nanometers -- another significant step toward a practical and repeatable combination of nanotechnology and quantum optics.


Story Source:

The above story is based on materials provided by American Institute of Physics. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. P. Hadden, J. P. Harrison, A. C. Stanley-Clarke, L. Marseglia, Y.-L. D. Ho, B. R. Patton, J. L. O’Brien, J. G. Rarity. Strongly enhanced photon collection from diamond defect centers under microfabricated integrated solid immersion lenses. Applied Physics Letters, 2010; 97 (24): 241901 DOI: 10.1063/1.3519847

Cite This Page:

American Institute of Physics. "Quantum cryptography? Physicists move closer to efficient single-photon sources." ScienceDaily. ScienceDaily, 17 March 2011. <www.sciencedaily.com/releases/2011/03/110316161914.htm>.
American Institute of Physics. (2011, March 17). Quantum cryptography? Physicists move closer to efficient single-photon sources. ScienceDaily. Retrieved February 28, 2015 from www.sciencedaily.com/releases/2011/03/110316161914.htm
American Institute of Physics. "Quantum cryptography? Physicists move closer to efficient single-photon sources." ScienceDaily. www.sciencedaily.com/releases/2011/03/110316161914.htm (accessed February 28, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, February 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Elon Musk's Hyperloop Moves Forward

Elon Musk's Hyperloop Moves Forward

Buzz60 (Feb. 27, 2015) Zipping around at 800-miles an hour is coming closer to reality in California. An entire town is being built around Elon Musk&apos;s Hyperloop concept and it wants you to stop in for a ride when it&apos;s ready. Brett Larson is on board. Video provided by Buzz60
Powered by NewsLook.com
Vibrating Bicycle Senses Traffic

Vibrating Bicycle Senses Traffic

Reuters - Innovations Video Online (Feb. 26, 2015) Dutch scientists have developed a smart bicycle that uses sensors, wireless technology and video to warn riders of traffic dangers. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
In Japan, Robot Dogs Are for Life -- And Death

In Japan, Robot Dogs Are for Life -- And Death

AFP (Feb. 25, 2015) Robot dogs are the perfect pet for some in Japan who go to repairmen-turned-vets when their pooch breaks down - while a full Buddhist funeral ceremony awaits those who don&apos;t make it. Duration: 02:40 Video provided by AFP
Powered by NewsLook.com
London Show Dissects History of Forensic Science

London Show Dissects History of Forensic Science

AFP (Feb. 25, 2015) Forensic science, which has fascinated generations with its unravelling of gruesome crime mysteries, is being put under the microscope in an exhibition of real criminal investigations in London. Duration: 00:53 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins