Navigation Links
Plasma as a fast optical switch
Date:11/8/2010

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. As shown in Fig. 1, 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.

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 Universitt (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 as shown in figure 2. 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.


'/>"/>

Contact: Saralyn Stewart
stewart@physics.utexas.edu
512-694-2320
American Physical Society
Source:Eurekalert

Related medicine news :

1. Restrictions on female plasma may not be warranted
2. Restrictions on Plasma From Female Donors May Need Revisiting
3. Inappropriate uses of frozen plasma
4. New York Sports Medicine Offers Platelet Rich Plasma Therapy For Treatment of Injury
5. After Teeth Are Pulled, Platelet-Rich Plasma May Speed Healing
6. Plasma protein appears to be associated with development and severity of Alzheimers disease
7. Researcher find fats galore in human plasma
8. Transitions Optical Partners With Dr. Aliza Through VidaySalud.com to Improve Visual Quality for Hispanics
9. First Virtual Optical Store Serves Military Personnel
10. Shamir Optical Industry Reports Fourth Quarter and Year-End 2009 Results
11. Mass. General Hospital to create registry for coronary optical coherence tomography
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... ... October 13, 2017 , ... ... Software Development, has been awarded a contract by the Center for Medicare and ... aims to accelerate the enterprise use of Agile methodologies in a consistent and ...
(Date:10/12/2017)... CA (PRWEB) , ... October 12, 2017 , ... ... Cheng, are now treating sleep apnea using cutting-edge Oventus O2Vent technology. ... a serious sleep disorder characterized by frequent cessation in breathing. Oral appliances can ...
(Date:10/12/2017)... (PRWEB) , ... October 12, 2017 , ... The American ... Excellence to Carol Friedman, PhD, FACMI, during the Opening Session of AMIA’s Annual Symposium ... 8. , In honor of Morris F. Collen, a pioneer in the field of ...
(Date:10/12/2017)... ... ... HMP , a leader in healthcare events and education, today announced that ... for ‘Best B-to-B Healthcare Website.’ Winners were announced during the Eddie & Ozzie Awards ... recognizes editorial and design excellence across a range of sectors. This year’s program included ...
(Date:10/12/2017)... ... October 12, 2017 , ... Health Literacy Innovations ... literacy software tool, and the Cancer Patient Education Network (CPEN), an independent professional ... announce a new strategic alliance. , As CPEN’s strategic partner, HLI will ...
Breaking Medicine News(10 mins):
(Date:9/27/2017)... -- Commended for their devotion to personalized service, SMP Pharmacy Solutions ... in the South Florida Business Journal,s 50 Fastest-Growing Companies, and ... the national specialty pharmacy has found its niche.  To that ... be honored by SFBJ as the 2017 Power Leader in ... receive his award in October, Bardisa said of the three ...
(Date:9/23/2017)... Pa. , Sept. 22, 2017 Janssen ... a complete response letter from the U.S. Food and ... seeking approval of sirukumab for the treatment of moderately ... letter indicates additional clinical data are needed to further ... moderately to severely active RA. ...
(Date:9/19/2017)... Sept. 19, 2017   ZirMed Inc ., a recognized ... announced that it has been ranked #1 by its users ... Rankings 2017 User Survey. ZirMed was recognized as the ... hospitals and medical centers over 200 beds and holds one ... technology user survey history. ...
Breaking Medicine Technology: