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Japan Shark Technology

Japanese Scientists Fire the Most Powerful Laser On the Planet 117

Posted by samzenpus from the amazing-laser dept.
Sepa Blackforesta writes: Scientist from University of Osaka claim have fired the world's most powerful laser. The beam was intact for 2-petawatt, pulse lasted just one picosecond. While it produced a huge amount of power, the energy required for the beam itself is equivalent to that needed to power a microwave for two seconds. An associate professor of electrical engineering at Osaka University Junji Kawanaka says “With heated competition in the world to improve the performance of lasers, our goal now is to increase our output to 10 petawatts.”
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Japanese Scientists Fire the Most Powerful Laser On the Planet More

Japanese Scientists Fire the Most Powerful Laser On the Planet

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  • It only lasted for a picosecond...

  • Why does anyone care? (Score:3)

    by quenda ( 644621 ) on Thursday July 30, 2015 @11:42PM (#50220461)

    Why should anyone care about the power level, as opposed to the pulse energy?
    ie why does it matter if the kilojoule is spread over one or ten picoseconds? Without this vital piece of information, it is hard to get excited (pardon the pun).

    • Re:Why does anyone care? (Score:5, Informative)

      by Noah Haders ( 3621429 ) on Friday July 31, 2015 @12:04AM (#50220535)

      Why should anyone care about the power level, as opposed to the pulse energy?

      people who have tattoos should care, for one. the ideal tattoo removal laser has really high instantaneous power but really short pulses. this way you get high power but low energy per pulse.

      the tattoo ink breaks down better with higher power lasers because it breaks the bonds holding the ink molecules together. but by keeping the energy per pulse low, you're minimizing the tissue damage since tissue damage grows with the amount of energy absorbed by the skin. when you break up the ink molecules into smaller pieces then the immune system can flush away the bits into your lymph nodes. tattoo is gone!

      • Re: (Score:2)

        by quenda ( 644621 )

        But does one vs ten picosecond matter?
        And I'm pretty sure you do not want a laser of this size pointed at your arm, unless you are looking for instant amputation.

        • Re:Why does anyone care? (Score:5, Interesting)

          by Anonymous Coward on Friday July 31, 2015 @12:49AM (#50220669)

          Timewise, atomic/molecular physics spans many orders of magnitude (from metastable states with lifetimes measured in hours, to inner-shell Auger processes with lifetimes measured in femtoseconds).

          However making short pulses isn't the true goal of lasers like this (A Q-switched laser that fits on a coffee table can make femtosecond pulses). The true thing of interest is the *number density of photons*. Since it's a laser, the photons have the same energy. Then the total number of photons is proportional to the energy in the pulse, but the *number density* - N/V - scales as the inverse of the spot size and the inverse of the duration (since duration = length / c).

          Therefore, the smaller the spot size and the shorter the pulse, the higher the number density of photons that is acheived in a given energy.

          When you have a high enough number density, nonlinear things (whose rate of occurrence is the number density of photons raised to the order of the nonlinearity) happen and nonlinear things are Generally Interesting. For example, a sufficiently high laser power is capable of literally blowing protons/neutrons out of an atomic nucleus - IF you can dump roughly a nucleon binding energy into an area the size of a nucleus, in less than the time it will try to radiate it away.

        • I don't think you would have felt it.

          Maybe. But it's not even close to being able to hurt you.

    • You can use high powered lasers in short pulses to compress and heat a fuel pellet to achieve fusion. A particular approach called fast ignition [wikipedia.org] requires a petawatt pulse. Given that the laser is named LFEX for "Laser for Fast Ignition Experiments", it is a good bet this is what it is for.

      (My expertise in this is limited to having had an inkling which Wikipedia article to look in for the answer. Further input from real experts is welcome.)

      • You can use high powered lasers in short pulses to compress and heat a fuel pellet to achieve fusion. A particular approach called fast ignition requires a petawatt pulse

        I think that should be "a very short pulse" -- but pulses used for ignition are much higher energy -- from 70kJ to 2MJ, according to your link.

        I would not believe anything in the article, though, since the writer seems to have a very poor grasp of basic physics:

        Two quadrillion wattsit self is a massive amount of output. The burst only

        • Re: (Score:1)

          by r0kk3rz ( 825106 )

          I think that should be "a very short pulse" -- but pulses used for ignition are much higher energy -- from 70kJ to 2MJ, according to your link.

          The HiPER [wikipedia.org] is a proposed project to experiment with this type of fusion, requiring the use of Petawatt scale lasers

          A 2 Petawatt pulse over 1 Picosecond isn't quite a 4 Petawatt pulse over 10 Picoseconds, but its on its way. Considering the organisation in TFA are now planning on scaling to produce 10 Petawatt pulse, maybe the timescale can be reduced for Ignition.

    • Re: (Score:1)

      by Anonymous Coward

      Higher instantaneous power leads to higher incidence of nonlinear effects. For example, if the power is high enough, there is so much photon density that two photons of some wavelength can appear as a single photon of half the wavelength to a molecule. This is used in two-photon microscopy, which will excite only a tiny region of a specimen to fluoresce and light up, giving much sharper images.

    • Re:Why does anyone care? (Score:5, Informative)

      by umafuckit ( 2980809 ) on Friday July 31, 2015 @01:47AM (#50220825)
      I don't know about those times scales, but femto-second pulsed lasers are damn useful for imaging [berkeley.edu]. Briefly, say the experimenter images green fluorescence. Normally, to get green fluorescence you need to excite with blue light of, say, 450 nm. However, if you can pack enough photons into a short packet then you can also get green fluorescence at about double the wavelength. It's called "two photon absorption" and won a Nobel prize. So you pump in 900 nm light and get back green. The advantage is that longer wavelengths are scattered less by biological tissue and, crucially, the depth of field is much better so there is very little out of focus emitted green light (see image in link). Because the laser scans over the specimen relatively slowly (e.g. a few times a second), you can collect scattered green photons and still assign them back to where they came from. So it's very efficient. Maybe this new laser will all for the process to work efficiently with 3 or even 4 photons.

    • Why should anyone care about the power level, as opposed to the pulse energy?
      ie why does it matter if the kilojoule is spread over one or ten picoseconds? Without this vital piece of information, it is hard to get excited (pardon the pun).

      Well, given that a 9mm has about the same energy as two or three punches... Yeah, I'd say the time and method of energy transfer/release is extremely important.

      Sources:
      https://en.wikipedia.org/wiki/... [wikipedia.org]
      http://www.science.ca/askascie... [science.ca]

    • Re: (Score:1)

      by r0kk3rz ( 825106 )

      Why should anyone care about the power level, as opposed to the pulse energy? ie why does it matter if the kilojoule is spread over one or ten picoseconds?

      I imagine this type of laser technology would be useful for Inertial Confinement Fusion [wikipedia.org] based projects.

    • Re: (Score:2)

      by drolli ( 522659 )

      * Because destruction free techniques like laser ablation are base on high local fields

      * because a 1ps pulse spreads over 10^12 Hz bandwidth, which may be useful if you want to have "more white" light (but this pulse is actually not very short)

      * because pump-probe techniques depend on short pulses. If you additionally need a strong pulse, higher power may come in handy

      * I also imagine it could be an advantage for generating plasma.

    • Why should anyone care about the power level, as opposed to the pulse energy?

      Thresholds, the same reason that the Large Hadron Collider may break apart subatomic particles while a 16 inch cannon cannot, even though the cannon delivers more total energy.

  • Making enormous swiss cheese!

  • Analogies? (Score:5, Funny)

    by marciot ( 598356 ) on Thursday July 30, 2015 @11:57PM (#50220509)

    Help me understand. Is a two petawatt laser being fired for a picosecond more like being sneezed on by a rhino with a cold or more like being shat on by an elephant with a bad case of explosive diarrhea?

  • -- [wolframalpha.com]
    Filter error: You can type more than that for your comment
  • Why would they need a laser to do this? It's like 3000 watt-seconds. That means the total dissipated energy used for, for example cutting a piece of metal, would be measured in energy used over time. In other words, that laser wouldn't cut a damn thing.
    • It is more like 2000 watt/seconds. Last I checked 2 petawatts / 1 picosecond will give you a 2 as the most significant digit...

    • Re: (Score:2)

      by wbr1 ( 2538558 )
      Lasers are not just used for cutting you insensitive clod.

      For instance, they can be attached to sharks instead.

      I came into this thread looking for sharks. I was disappointed and decided to remedy the situation.

  • Which planet? Alderaan?

  • If I only worked for 1 picosecond... (Score:5, Funny)

    by SlithyMagister ( 822218 ) on Friday July 31, 2015 @12:36AM (#50220641)
    I'd get fired too

    • Re: (Score:2)

      by _merlin ( 160982 )

      Yeah, I was reading it as though the object would be a job title, as in "Japanese Scientists Fire the Most Powerful CEO On the Planet". Now that would be a real achievement.

  • Godzilla? (Score:1, Redundant)

    by DrNico ( 691592 )
    Is nobody going to mention Godzilla?

    • Re: (Score:1)

      by TimSSG ( 1068536 )

      Is nobody going to mention Godzilla?

      I was going to ask how large does the shark have to be to have this laser mounted on it. But, maybe Godzilla would be a better Lazar platform. Tim S.

  • The next step... (Score:3, Funny)

    by turbinicarpus ( 4203715 ) on Friday July 31, 2015 @12:48AM (#50220665)
    "We are currently working on mounting this laser on a giant robot," added Professor Kawanaka.

  • "enough energy to warm up your breakfast burrito for two full seconds"

    *stunned in awe*

    So, since the experiment is effectively useless, some information on whether the same technology scales and what sort of energy would be required to heat a burrito for like, 2 minutes. Or does it not scale, so conveniently leaves that type of information out?

  • ...it's LASER... it's an acronym: Light Amplification by Stimulated Emission of Radiation... why can't anyone ever get it right? It's not "laser" and it's not "Laser", it's f'ing LASER! (well, I suppose if we REALLY want to be pedantic it's actually L.A.S.E.R. ... but even I'm not that much of an asshole).

    • it's LASER as long as you pronounce it "ell ey ess ee ar". What, you dont? Then why dont you stop nitpicking, and just accept that at some point, a pronouneable acronym becomes a new word.

    • Re: (Score:2)

      by gsslay ( 807818 )

      Lol, this is a snafu, isn't it? We do have nimbies like yourself to put a stop to this kind of thing, but perhaps a quango should be set up to enforce it? People who insist in turning acronyms into words should be tasered and their zip code published online, so we can be sure they're on everyone's radar.

      I shall get a faq written up on this dangerous problem.

    • LASER is what is happening. laser is the name of the device.

  • Clicked in the link and got;-

    Executing in an invalid environment for the supplied user

    Does that mean they lasered the webserver for me?

    • Re: (Score:2)

      by cfalcon ( 779563 )

      It means you either supplied an invalid user for the environmental execution in question, or you supplied an invalid user for the execution environment. You should see to that. I hear there is a pill.

  • Would they be Class C, Class D? Be specific, I'm trying to figure out how long a Cree would last connected in series to a three bar electric fire.

  • But can it fill a house with popcorn from that short burst?

  • 2 megawatts can't melt steel beams.

  • ...of a Slashdot where the editors actually edit submissions and turn them into something approaching standard English.

    When actual fucking EDITING commences, I'll consider that worth coming up with the bucks to fly out to Oregon and meet you guys at *Con. Thanks for the invite, though.

  • Meanwhile, there's this other bit of news that's gone mostly unnoticed outside Japan: http://www.japantimes.co.jp/ne... [japantimes.co.jp] Surely this must be coincidence, right? I think not! https://en.wikipedia.org/wiki/... [wikipedia.org]
  • Comment removed based on user account deletion

  • Story only valid if scientist laughed maniacally before/during/after firing the worlds largest laser...

  • As many have pointed out 2 kJ 500 TW (goal power output of NIF) https://en.wikipedia.org/wiki/... [wikipedia.org]
  • excerpt from article. "Two quadrillion wattsit self is a massive amount of output. The burst only lasted about one picosecond (1/1,000,000,000,000 of a second), so while the energy output was incredibly large, the actual amount of power (energy divided by time) the LFEX used wasn’t all that big. When it was all said and done, the laser only produced enough power to run a microwave for about two seconds." they are wrong on this one. It's actually invers to how they explain. it's High Power - like in

  • Americans have mastodonic laser.

  • What does an out of work laser do?
    Light up the night sky?
    Send a message to Alpha Centauri?
    Flash incinerate your pop corn?

  • Yet the japanese are building the Death Star http://www.newser.com/story/16... [newser.com]

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