Exawatt laser pulses just one of the topics at OSA's Frontiers in Optics

October 1, 2009--Todd Ditmire of the University of Texas will talk about the present and future of the university's Texas Petawatt Laser program at the Optical Society's (OSA's) Annual Meeting, Frontiers in Optics (FiO; Oct. 11 to 15, 2009, San Jose, CA).

October 1, 2009--Todd Ditmire of the University of Texas will talk about the present and future of the university's Texas Petawatt Laser program at the Optical Society's (OSA's) Annual Meeting, Frontiers in Optics (FiO; Oct. 11 to 15, 2009, San Jose, CA). At present producing pulses at the petawatt (1015 W) power level, the laser could reach the exawatt (1018 W) power level with modifications.

Laser fusion in Texas
The Texas Petawatt Laser currently produces petawatt power through a process of chirping, in which a short light pulse (150 fs in duration) is stretched out in time. This resulting longer pulse is amplified to higher energy and then recompressed to its shorter duration, thus providing a modest amount of energy, 190 J, in a very brief interval.

Ditmire claims that his petawatt device has the highest power of any laser system now operating, even the one at the National Ignition Facility at the Lawrence Livermore National Lab (Livermore, CA), owing to the very short pulse compression he and his colleagues use.

The main research use for the Texas Petawatt Laser has been to produce thermonuclear fusion; the laser light strikes a target where fusion of light nuclei occurs, releasing neutrons into the vicinity. These neutrons can themselves be used for doing research. The first results of this fusion experiment will be presented in Ditmire's talk at the OSA meeting. Other applications include the study of hot dense plasmas at pressures billions of time higher than atmospheric pressure and the creation of conditions for accelerating electrons to energies of billions of electron volts.

Another figure of merit for a laser, in addition to power, is power density. The Texas device is capable of producing power densities exceeding 1021 W/cm2. At this level, many novel interactions might become possible.

To get to exawatt powers, Ditmire hopes to combine largely existing laser technology and his already tested 100 fs pulses with new laser-glass materials that would allow amplification up to energies of 100 kJ. The laser's 190 J current energy level is typical of laser labs at or near the petawatt level, such as those in Oxford, England; Osaka, Japan; and Rochester, NY. With support from the government and the research community, building an exawatt laser might take the years to achieve, Ditmire estimates.

Ditmire's paper, FTuK2, "The Texas Petawatt Laser and Technology Development toward an Exawatt Laser," will be presented at 11 a.m. on Tuesday, Oct. 13.

(And, of course, many more topics will be presented at FiO. A small sampling: A Special Symposium--The Future of 3-D Television; 1,001 Cameras See in Gigapixels; All That Glitters is Now Gold; Prehistoric Bear Diet Revealed by Laser Archaeology; and Illumination-Aware Imaging. For details, see: http://www.frontiersinoptics.org/)


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--posted by John Wallace, johnw@pennwell.com

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