World’s most powerful laser fired up

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World’s most powerful laser fired up

Austin (TX) – Researchers at the University of Texas at Austin have turned on the Texas Petawatt laser on March 31 for, well, a very brief period of time. The specs of the device are mind-boggling: It has the power output of thousands of power plants and is brighter than the surface of the sun. Yet, the total power output of the atom-splitting laser is just enough to keep a light bulb burning for only a few seconds.

The laser achieved a power of more than 1 Petawatt this week, nearing the 1.5 Petawatt peak performance of the Lawrence Livermore Petawatt laser that went into operation in 1996 and was closed down in 1999 (to make room for the National Ignition Facility). One Petawatt is one quadrillion watts (in numbers: 1,000,000,000,000,000).

Currently being the only operating Petawatt laser in the United States, the Texas laser is claimed to have a power output of more than 2000 times the entire electrical generating capacity in the United States. The laser is generated using 20 20,000-volt capacitors that retrieve electricity from the University of Texas’s power grid. Over several stages of tubes and sheets of glass, the laser beam is amplified and is eventually concentrated at a point with the diameter of a human hair.  

Of course, this massive amount of energy created cannot be sustained over a longer period of time. In fact, the Texas Petawatt laser unloads is energy within 100 femtoseconds, which is 1/10th of a trillionth of a second (0.0000000000001 seconds). In that time frame the target gets exposed to 200 joules of energy, which is enough to split atoms and simulate supernovas, tabletop stars and very high-density plasmas that mimic exotic stellar objects known as brown dwarfs. In practical life and applied to a larger surface, this energy isn’t huge and just enough to run a light bulb for about two seconds.

“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 Todd Ditmire, who is leading the project.

The Lawrence Livermore Petawatt laser was significantly more powerful. According to the specifications available on the Internet, the device achieved 680 joules on an area with a diameter of 1054 nm. The lab was also able to sustain the laser over a longer period of time, half a picosecond (0.0000000000005 seconds), to be exact.  

The total cost of the Texas Petawatt laser is estimated at about $7 million. It is housed in an underground bay near Robert Lee Moore Hall on Speedway. The three-story bay previously contained the Texas Experimental Tokamak (TEXT), a plasma-confining device used by the Physics Department for fusion energy studies.