Navigation Links
Plasma as a fast optical switch

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
American Physical Society

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 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:
(Date:11/27/2015)... ... November 27, 2015 , ... The rapid speed at which ... age, more care is needed, especially with Alzheimer’s, dementia and other cognitive conditions ... overworked. The forgotten part of this equation: 80 percent of medical care occurs ...
(Date:11/27/2015)... Orange County, CA (PRWEB) , ... November 27, 2015 , ... ... holiday season , The company is offering customers 10% off of their purchase of ... purchase any treatment at full price. According to a company spokesperson. “Finding lice is ...
(Date:11/27/2015)... VVA (PRWEB) , ... November 27, 2015 , ... ... motto of progress through sharing, the 2016 Building Better Radiology Marketing ... The conference will begin on Sunday, March 6, 2016, at Caesars Palace in ...
(Date:11/27/2015)... (PRWEB) , ... November 27, 2015 , ... ... Health-E-minds, an innovative online platform for mental health and wellness consultation, has collaborated ... This partnership will bridge the knowledge gap experienced by parents and bring advice ...
(Date:11/27/2015)... (PRWEB) , ... November 27, 2015 , ... Avid collector, ... Ann Arbor Michigan boxing style concert posters. This is one of Joplin's most famous ... Canterbury House at the University of Michigan in Ann Arbor. The According to Hawley, ...
Breaking Medicine News(10 mins):
(Date:11/27/2015)... 26, 2015 ... the "2016 Global Tumor Marker Testing ... and Sales Segment Forecasts, Innovative Technologies, Instrumentation ... to their offering. --> ... "2016 Global Tumor Marker Testing Market: ...
(Date:11/26/2015)... WILMINGTON, North Carolina , 26 november ... Laboratories, Inc. (AAIPharma/CML) kondigt de geplande investering ... de uitbreiding van de laboratoria en het ... . De uitbreiding zal resulteren in ... waarmee wordt voldaan aan de groeiende behoeften ...
(Date:11/26/2015)... , November 26, 2015 --> ... to use SyMRI to find optimal contrast weighting of MRI ... metastases, and has signed a research agreement with SyntheticMR in ... hospital. Using SyMRI, it is possible to generate multiple contrast ... after the patient has left, thus making it possible to ...
Breaking Medicine Technology: