Featured Research

from universities, journals, and other organizations

'Dark Pulse Laser' produces bursts of ... almost nothing

Date:
June 11, 2010
Source:
National Institute of Standards and Technology (NIST)
Summary:
In an advance that sounds almost Zen, researchers have demonstrated a new type of pulsed laser that excels at not producing light.

Colorized trace of pulses from the NIST/JILA "dark pulse" laser, indicating the light output nearly shuts down about every 2.5 nanoseconds.
Credit: Talbott/NIST

In an advance that sounds almost Zen, researchers at the National Institute of Standards and Technology (NIST) and JILA, a joint institute of NIST and the University of Colorado at Boulder, have demonstrated a new type of pulsed laser that excels at not producing light. The new device generates sustained streams of "dark pulses" -- repeated dips in light intensity -- which is the opposite of the bright bursts in a typical pulsed laser.

Related Articles


Despite its ominous name, the dark pulse laser is envisioned as a tool for benign communications and measurements based on infrared light frequencies. The laser's ultrashort pulses span just 90 picoseconds (trillionths of a second), making the device suitable for measurements on short timescales. Dark pulses might be useful in signal processing because, unlike bright pulses, they generally propagate without distortion. Dark pulses might be used like a camera shutter for a continuous light beam in optical networks.

Described in Optics Express, the new NIST/JILA technology is the first to generate dark pulses directly from a semiconductor laser cavity, without electrical or optical shaping of pulses after they are produced. The chip-sized infrared laser generates light from millions of quantum dots (qdots), nanostructured semiconductor materials grown at NIST. Quantum dot lasers are known for unusual behavior.

In the new NIST/JILA laser, small electrical currents are injected into the laser, causing the qdots to emit light. The qdots are all about the same size -- about 10 nanometers (billionths of a meter) wide -- and thus, because of a nanostructured design that makes them behave like individual atoms, all emit light at the same frequency. The current generates enough energy to amplify the emissions from the collective dots, creating the special properties of laser light.

The new laser depends on the qdots' unusual energy dynamics, which have the effect of stabilizing dark pulses. After emitting light, qdots recover energy from within rapidly (in about 1 picosecond) but more slowly (in about 200 picoseconds) from energy inputs originating outside the qdots in the laser cavity. This creates a progression of overall energy gains gradually giving way to overall energy losses. Eventually, the laser reaches a steady state of repeated brief intensity dips -- a drop of about 70 percent -- from the continuous light background.

The dark pulse laser was developed through close collaborations between NIST experts in qdot growth and semiconductor laser design and fabrication, and JILA experts in ultrafast lasers and related measurements. NIST has ongoing research efforts to develop quantum dot lasers and to develop modeling, fabrication, and measurement methods for semiconductor nanostructures such as quantum dots. In general, semiconductor lasers are being considered for many advanced applications, such as next-generation atomic clocks based on optical frequencies, for which large lasers are costly and complex.


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.


Journal Reference:

  1. Mingming Feng, Kevin L. Silverman, Richard P. Mirin, Steven T. Cundiff. Dark pulse quantum dot diode laser. Optics Express, 2010; 18 (13): 13385 DOI: 10.1364/OE.18.013385

Cite This Page:

National Institute of Standards and Technology (NIST). "'Dark Pulse Laser' produces bursts of ... almost nothing." ScienceDaily. ScienceDaily, 11 June 2010. <www.sciencedaily.com/releases/2010/06/100609171804.htm>.
National Institute of Standards and Technology (NIST). (2010, June 11). 'Dark Pulse Laser' produces bursts of ... almost nothing. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2010/06/100609171804.htm
National Institute of Standards and Technology (NIST). "'Dark Pulse Laser' produces bursts of ... almost nothing." ScienceDaily. www.sciencedaily.com/releases/2010/06/100609171804.htm (accessed October 26, 2014).

Share This



More Matter & Energy News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) 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