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Shark Science

Is There a Limit To a Laser's Energy? 135

StartsWithABang (3485481) writes "For normal matter — things like protons, neutrons and electrons — there's a fundamental limit to the number of particles you can fit into a given region of space thanks to the Pauli exclusion principle. But photons aren't subject to that limit; in theory, you could cram an infinite number of them into the same exact state. In principle, then, couldn't you create a laser (or lasing cavity) with an infinite amount of energy inside? Perhaps, but there are some big challenges to be overcome!"
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Is There a Limit To a Laser's Energy?

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  • E=MC^2 (Score:2, Interesting)

    by Anonymous Coward on Sunday May 04, 2014 @04:07AM (#46911773)

    Eventually the laser energy will create a black hole, provided some other exotic effect doesn't occur first. Realisitcally though it's not possible to attain those kinds of photon densities (nothing can reflect anywhere close to well enough for starters).

  • by Chas ( 5144 ) on Sunday May 04, 2014 @05:13AM (#46911893) Homepage Journal

    Okay. Interesting on a theoretical level.

    The main problem with testing this is "how does one generate infinite or near-infinite energy" to power something like this?

    Of course, if we've answered that, we're ALREADY in a place where we've either wiped ourselves out (accidentally or otherwise), or we've basically solved the greatest real-world problem in the history of humanity.

  • Re:Oblig. XKCD (Score:5, Interesting)

    by FatLittleMonkey ( 1341387 ) on Sunday May 04, 2014 @05:57AM (#46911951)

    Yes [xkcd.com].

  • by drolli ( 522659 ) on Sunday May 04, 2014 @07:16AM (#46912089) Journal

    But long before that happens the question is if the laser can remain a laser.

    A laser needs some kind of nonlinearity in the medium. Any nonlinearity introduces a scale. So the real question is: At which power does of-resonant driving cause transitions (e.g. Landau-Zener) or of-resonant shifts (Stark shift) and can you actually theoretically contruct a medium which fulfills the criteria to serve as a lasing medium for an arbitrary large scale of power?

    As a starting point for an examination of such questions i recomment the Quantum Optics Toolbox for Matlab by Sze Tan.

  • Old news? (Score:5, Interesting)

    by KClaisse ( 1038258 ) on Sunday May 04, 2014 @07:42AM (#46912169)
    There was an article from 2010 that talked about the theoretical limit to laser beam energy. From the article:

    "At high laser intensities interaction of the created electron and positron with the laser field can lead to production of multiple new particles and thus to formation of an avalanche-like electromagnetic cascade"

    Here's the link to the article in question: http://physicsbuzz.physicscent... [physicscentral.com]

    That article was ultimately using this [nytimes.com] article as a source.
  • E=mc^2 (Score:4, Interesting)

    by ILongForDarkness ( 1134931 ) on Sunday May 04, 2014 @11:23AM (#46912933)

    At high enough energies particles are spontaneously created. They in turn will obey Pauli Exclusion (at least if they have spin I think). So enough photons and you make matter that will prevent you from making more particles ie pumping more energy into the space.

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