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.

"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 August 20, 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 August 20, 2014).

Share This




More Matter & Energy News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

AFP (Aug. 19, 2014) A solar cell that resembles a flower is offering a new take on green energy in Japan, where one scientist is searching for renewables that look good. Duration: 01:29 Video provided by AFP
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. Video provided by Newsy
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:
from the past week

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