Most powerful laser in the world fires up
April 8, 2008
Dr. Todd Ditmire directs the Texas Petawatt project.
The Texas Petawatt laser reached greater than one petawatt of laser power on Monday morning, March 31, making it the highest powered laser in the world, Todd Ditmire, a physicist at The University of Texas at Austin, said.
The Texas Petawatt is the only operating petawatt laser in the United States.
Ditmire says that when the laser is turned on, it has the power output of more than 2,000 times the output of all power plants in the United States. (A petawatt is one quadrillion watts.) The laser is brighter than sunlight on the surface of the sun, but it only lasts for an instant, a 10th of a trillionth of a second (0.0000000000001 second).
Ditmire and his colleagues at the Texas Center for High-Intensity Laser Science will use the laser to create and study matter at some of the most extreme conditions in the universe, including gases at temperatures greater than those in the sun and solids at pressures of many billions of atmospheres.
This will allow them to explore many astronomical phenomena in miniature. They will create mini-supernovas, tabletop stars and very high-density plasmas that mimic exotic stellar objects known as brown dwarfs.
“We can learn about these large astronomical objects from tiny reactions in the lab because of the similarity of the mathematical equations that describe the events,” said Ditmire, director of the center.
Such a powerful laser will also allow them to study advanced ideas for creating energy by controlled fusion.
Source: University of Texas at Austin
Nov 02, 2009 |
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Roughly what they do is generate a very short low power pulse. Since it's very short it can't be monochromatic; this is a result from fourier analysis. Consider a bell curve in the frequency domain, the only way all those sine curves can give a large net contribution is if their phases are roughly aligned at some point, this is at the center of the pulse. Turns out that the smaller the pulse is in time, the broader the range of frequencies involved must be to quickly cancel out at either end of the pulse.
Since the initial pulse contains a spread of frequencies you can use gratings or prisms to get different frequency components to arrive at a power amplifier at different times(this is known as the strecher); the amplified pulse can then be compressed again when it comes out the other end using prisms or gratings.