Featured Research

from universities, journals, and other organizations

Quantum Dots Deliver Photons One At A Time

Date:
March 1, 2004
Source:
National Institute Of Standards And Technology (NIST)
Summary:
A National Institute of Standards and Technology (NIST) scientist has demonstrated efficient production of single photons---the smallest pulses of light---at the highest temperatures reported for the photon source used.

A National Institute of Standards and Technology (NIST) scientist has demonstrated efficient production of single photons---the smallest pulses of light---at the highest temperatures reported for the photon source used. The advance is a step toward practical, ultrasecure quantum communications, as well as useful for certain types of metrology. The results are reported in the Feb. 23 issue of Applied Physics Letters.

Related Articles


"Single photon turnstiles" are being hotly pursued for quantum communications and cryptography, which involve using streams of individual photons in different quantum states to transmit encoded information. Due to the peculiarities of quantum mechanics, such transmissions could not be intercepted without being altered, thus ensuring that eavesdropping would be detected.

The photon source used in the NIST study was a "quantum dot," 10 to 20 nanometers wide, made of semiconductor materials. Quantum dots have special electronic properties that, when excited, cause the emission of light at a single wavelength that depends on dot size. An infrared laser tuned to a particular wavelength and intensity was used to excite the quantum dot, which produced photons one by one more than 91 percent of the time at temperatures close to absolute zero (5 K or about minus 459 degrees F) and continued to work at 53 percent efficiency at 120 K (minus 243 degrees F). Higher operating temperatures are preferable from a cost standpoint, because the need for cooling is reduced.

The NIST quantum dots are made of indium gallium arsenide, can be fabricated easily, and can be integrated with microcavities, which increase photon capture efficiency. According to NIST electrical engineer Richard Mirin, this design offers advantages over other single photon sources, many of which exhibit blinking, stop working under prolonged exposure to light or are difficult to fabricate.


Story Source:

The above story is based on materials provided by National Institute Of Standards And Technology (NIST). Note: Materials may be edited for content and length.


Cite This Page:

National Institute Of Standards And Technology (NIST). "Quantum Dots Deliver Photons One At A Time." ScienceDaily. ScienceDaily, 1 March 2004. <www.sciencedaily.com/releases/2004/02/040229232522.htm>.
National Institute Of Standards And Technology (NIST). (2004, March 1). Quantum Dots Deliver Photons One At A Time. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2004/02/040229232522.htm
National Institute Of Standards And Technology (NIST). "Quantum Dots Deliver Photons One At A Time." ScienceDaily. www.sciencedaily.com/releases/2004/02/040229232522.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com
Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) Video provided by AP
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