Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. Military Space News .




MILITARY COMMUNICATIONS
Advancing secure communications: A better single-photon emitter for quantum cryptography
by Staff Writers
Ann Arbor MI (SPX) Apr 10, 2013


File image.

In a development that could make the advanced form of secure communications known as quantum cryptography more practical, University of Michigan researchers have demonstrated a simpler, more efficient single-photon emitter that can be made using traditional semiconductor processing techniques.

Single-photon emitters release one particle of light, or photon, at a time, as opposed to devices like lasers that release a stream of them. Single-photon emitters are essential for quantum cryptography, which keeps secrets safe by taking advantage of the so-called observer effect: The very act of an eavesdropper listening in jumbles the message. This is because in the quantum realm, observing a system always changes it.

For quantum cryptography to work, it's necessary to encode the message-which could be a bank password or a piece of military intelligence, for example-just one photon at a time. That way, the sender and the recipient will know whether anyone has tampered with the message.

While the U-M researchers didn't make the first single-photon emitter, they say their new device improves upon the current technology and is much easier to make.

"This thing is very, very simple. It is all based on silicon," said Pallab Bhattacharya, the Charles M. Vest Distinguished University Professor of Electrical Engineering and Computer Science, and the James R. Mellor Professor of Engineering.

Bhattacharya, who leads this project, is a co-author of a paper on the work published in Nature Communications on April 9.

Bhattacharya's emitter is a single nanowire made of gallium nitride with a very small region of indium gallium nitride that behaves as a quantum dot. A quantum dot is a nanostructure that can generate a bit of information. In the binary code of conventional computers, a bit is a 0 or a 1. A quantum bit can be either or both at the same time.

The semiconducting materials the new emitter is made of are commonly used in LEDs and solar cells. The researchers grew the nanowires on a wafer of silicon. Because their technique is silicon-based, the infrastructure to manufacture the emitters on a larger scale already exists. Silicon is the basis of modern electronics.

"This is a big step in that it produces the pathway to realizing a practical electrically injected single-photon emitter," Bhattacharya said.

Key enablers of the new technology are size and compactness.

"By making the diameter of the nanowire very small and by altering the composition over a very small section of it, a quantum dot is realized," Bhattacharya said. "The quantum dot emits single-photons upon electrical excitation."

The U-M emitter is fueled by electricity, rather than light-another aspect that makes it more practical. And each photon it emits possesses the same degree of linear polarization. Polarization refers to the orientation of the electric field of a beam of light. Most other single-photon emitters release light particles with a random polarization.

"So half might have one polarization and the other half might have the other," Bhattacharya said. "So in cryptic message, if you want to code them, you would only be able to use 50 percent of the photons. With our device, you could use almost all of them."

This device operates at cold temperatures, but the researchers are working on one that operates closer to room temperature.

The paper is titled "Electrically-driven polarized single-photon emission from an InGaN quantum dot in a GaN nanowire." The first author is Saniya Deshpande, a graduate student in electrical engineering and computer science. The work is supported by the National Science Foundation. The device was fabricated at the U-M Lurie Nanofabrication Facility.

.


Related Links
University of Michigan
Read the latest in Military Space Communications Technology at SpaceWar.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





MILITARY COMMUNICATIONS
Northrop Grumman Awarded U.S. Navy Contract to Upgrade, Enhance NGC2P Tactical Data Link Processor
San Diego CA (SPX) Apr 09, 2013
The U.S. Navy has awarded Northrop Grumman an $80 million contract to upgrade and enhance the Next Generation Command and Control Processor (NGC2P). The NGC2P system is a tactical data link communication processor that provides critical real-time information about friendly and enemy activity during combat operations. The five-year, indefinite-quantity, indefinite-delivery NGC2P Techn ... read more


MILITARY COMMUNICATIONS
US to intercept N.Korea missile if allies at risk: admiral

Japan deploys anti-North Korean missiles in Tokyo

US boosts missile defence, N. Korea warns of nuclear strike

US boosts missile defence, N. Korea warns of nuclear strike

MILITARY COMMUNICATIONS
S. Korea says North's missile launch may be imminent

N. Korea missile movements fuel tensions

Raytheon receives Rolling Airframe Missile contract

Taiwan to aim 50 medium-range missiles at China: report

MILITARY COMMUNICATIONS
India uses drones to fight rhino poaching

Gilat Showcases its Lightweight Compact Satellite Communications Solution for UAVs at LAAD 2013

French military considering purchase of US drones: source

US Congress hears calls for drone safeguards

MILITARY COMMUNICATIONS
Fourth Lockheed Martin MUOS Satellite Entering System Test as Communication Module and Multi-Beam Antenna Installed

Advancing secure communications: A better single-photon emitter for quantum cryptography

Northrop Grumman Awarded U.S. Navy Contract to Upgrade, Enhance NGC2P Tactical Data Link Processor

Soldiers and Families Can Suffer Negative Effects from Modern Communication Technologies

MILITARY COMMUNICATIONS
Lockheed Martin to Provide US Army with Simulation-Based Command and Battle Staff Training System

Cobra Judy Replacement radars perform exceptionally during first live-launch test

Lockheed Martin Demonstrates Gyrocam Sensor Maritime Capability with US Navy

Nanofoams could create better body armor

MILITARY COMMUNICATIONS
Latin America's top defense trade expo opens in Rio

Lagardere launches sale of stake in EADS

Israeli defense industry eyes Turkey again

Hagel urges changes to US military judicial system

MILITARY COMMUNICATIONS
Japan, Taiwan near accord on disputed isles fishery

Three Chinese ships in disputed waters: Japan

Syria, N.Korea to dominate G8 foreign ministers talks

China, Australia agree on annual PM meetings

MILITARY COMMUNICATIONS
Imaging methodology reveals nano details not seen before

Glass-blowers at a nano scale

Nanoparticles show promise as inexpensive, durable and effective scintillators

Scientists develop innovative twists to DNA nanotechnology




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement