Featured Research

from universities, journals, and other organizations

Plasma as a fast optical switch

Date:
November 9, 2010
Source:
American Physical Society
Summary:
Physicists are presenting new research on a laser that uses relativistic effects to turn otherwise opaque plasma transparent, creating an ultra-fast optical switch useful in next-generation particle accelerators.

Just like an electrical switch allows the flow of electricity into electrical circuits, relativistic transparency in plasma can act like a fast optical switch allowing the flow of light through otherwise opaque plasma. Modern day lasers, such as the Trident laser in Los Alamos National Laboratory delivers a 200 terawatt power pulse (roughly 400 times the average electrical consumption of the United States) in half a trillionth of a second (picosecond) time. When the laser power reaches a threshold limit, relativistic transparency in plasma turns the initially opaque plasma transparent in less than a tenth of a picosecond.

Related Articles


Powerful lasers are used to drive plasmas in next-generation particle accelerators and x-ray beams. One shortcoming of these beams is that they typically have a range of energy, caused by the gradual rise of laser power from zero to its maximum level. Using an optical switch, this ramp up time can be reduced to less than a tenth of a picosecond, delivering peak laser power to the plasma on a faster time scale.

So, how does this relativistic transparency happen inside plasma? When a laser beam is incident on (or strikes) plasma, electrons in the plasma react to the laser to cancel its presence inside the plasma. But when the laser is powerful enough to accelerate electrons close to the speed of light, the mass of the electrons increases, making them "heavier." These heavier electrons cannot react quickly enough; hence the laser beam propagates through the plasma.

Now, for the first time, scientists at Los Alamos National Laboratory and Ludwig-Maximilian Universitδt (LMU) in Germany have been able to make a direct observation of relativistic transparency in thin plasmas using a Frequency-Resolved Optical Gating (FROG) device. The discovery was made possible by two key capabilities: the ability to fabricate carbon foils a few nanometers thick to produce thin plasma, and the elimination of optical noise preceding the Trident laser pulse on a few picosecond timescale.

Initially, the researchers observed pulse shortening due to relativistic transparency and consistent spectral broadening. Later, they also measured the shape of the laser pulses incident on and transmitted through the plasma to directly observe the transparency. The transmitted laser pulse is roughly half the duration of the incident laser pulse, with a transparency turn on time around a fifth of a picosecond. The experimental results are well consistent with that of computer simulation, except the loss of fast turn-on time due to propagation effects arising from diffraction. Efforts are currently underway to eliminate diffraction limitations to observe the true turn-on time.

Researchers are presenting their work at the 52nd annual meeting of the American Physical Society's Division of Plasma Physics, being held in Chicago Nov. 8-12.


Story Source:

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


Cite This Page:

American Physical Society. "Plasma as a fast optical switch." ScienceDaily. ScienceDaily, 9 November 2010. <www.sciencedaily.com/releases/2010/11/101108071922.htm>.
American Physical Society. (2010, November 9). Plasma as a fast optical switch. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/11/101108071922.htm
American Physical Society. "Plasma as a fast optical switch." ScienceDaily. www.sciencedaily.com/releases/2010/11/101108071922.htm (accessed October 25, 2014).

Share This



More Matter & Energy News

Saturday, October 25, 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