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Science

Tractor Beams Are Getting Closer (Sort of) 70

Posted by CmdrTaco from the thats-no-moon dept.
xt writes "A recently submitted paper in arXiv claims that by using Bessel beams it is theoretically possible to pull particles towards the light source, opening up new avenues for optical micromanipulation (the direction of the force is size dependent, so it could be used for particle sorting). There is also a simpler article translated in English (original article in Greek)."
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Tractor Beams Are Getting Closer (Sort of) More

Tractor Beams Are Getting Closer (Sort of)

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  • There's something strangely attractive about this idea...

  • We have (quantum) teleporters and (quantum) tractor beams now? What's next, (quantum) warp drives?

  • There should be some formula. For every 1,000,000 articles produced about something that's theoretically possible, 1 results in an actual practical application.

    • True. But it makes for good stories to fill-up Asimov's Science-based fiction. "Well it's theoretically possible to build a tractor beam" - random author

      • Science fiction technologies can be divided into two classes. Those which are merely incredibly difficult, and those to which the laws of physics have raised a comic middle finger to our dreams.

        The former include interstellar travel, nano-assemblers, immortality and brain uploading. The latter perpetual motion, time travel, antigravity and anything faster than light. Anything in the first category you can hope will, one day, be achiveable... even though it may take centuries of advancement.

        I'm not sure wh

        • I would say faster than light travel straddles the categories. Time travel may as well. Theoretical Physicist Michio Kaku has written about possibilities for both. While I'm not holding out hope to ever see either of these, if we could somehow figure out how to create wormholes, for example, (which I would put in the 'incredibly difficult' category until it's proven otherwise) those could potentially be used for both (though I'll admit, I'm rather skeptical of the claims that they could be used for time tra

          • Re: (Score:2)

            by Thing 1 ( 178996 )

            Strictly speaking I suppose you aren't violating that law, you're just finding a way around it.

            Interesting -- I was just reading that other article about the patent trolls getting sued by the Google and Microsoft team, and this sentence seemed to fit both articles. :)

        • Re: (Score:2)

          by ceoyoyo ( 59147 )

          Faster than light and time travel are both admitted as possibilities by the laws of physics as we know them. Depending on what you mean by antigravity, it probably is too.

        • I think it may be possible for information to travel faster than light. Remember that during the inflationary period following the big bang, the universe expanded at a rate several magnitudes greater than the speed of light. No, I don't think it is possible for people to travel faster than light and still maintain their structural integrity. And I agree, anything that violates the law of causality bothers the heck out of me.

          Tractor beams... well, until we fully understand how gravity fits into unified fie

        • Re: (Score:2)

          by Gilmoure ( 18428 )

          Ah, well, now that that's settled, we can get back to deciding who's hotter; Princess Leia or Queen Natalie Portman.

        • The former include interstellar travel, nano-assemblers, immortality and brain uploading. The latter perpetual motion, time travel, antigravity and anything faster than light. Anything in the first category you can hope will, one day, be achiveable... even though it may take centuries of advancement.

          Let's hope either immortality or at least brain uploading is one of the first ones then.

        • I think it's incredibly optimistic to think that true physical immortality will ever be possible (copying your conscious thoughts onto the internet doesn't count, IMHO).
  • I thought items get closer to them. Or is this a relativity thing?

  • Particle sorting...Isotopes, perhaps? (Score:5, Interesting)

    by dfetter ( 2035 ) <david@fetter.org> on Thursday March 03, 2011 @01:22PM (#35370468) Homepage Journal

    Actually, this could be pretty significant if it takes some clever machine rather than a host of gigantic centrifuges to do the job.

    • Re:Particle sorting...Isotopes, perhaps? (Score:5, Informative)

      by Anonymous Coward on Thursday March 03, 2011 @01:58PM (#35370880)

      The wavelengths at which different isotopes absorb light are slightly different (Hyperfine structure [wikipedia.org]), so if you tune the wavelength of your laser just right, you can use radiation pressure [wikipedia.org] rather than the (typically weaker) optical gradient force [wikipedia.org] to at least identify different isotopes. (I work in cold atom physics and was just doing this in the lab with Rubidium 85 and 87).

      However, the radiation pressure on an atom is limited by the atom, whereas the optical gradient force is limited by the power of your laser. At room temperature, you can't use radiation pressure to separate Rb 85 and 87. There is considerably more freedom to engineer the forces experienced by the particle if you use the optical gradient forces and tricks, like Bessel beams, or more generally SLMs [wikipedia.org], which are essentially computer-programmable holograms. See, for example, the excellent experimental work of the Dholakia [st-andrews.ac.uk] and Padgett [gla.ac.uk] groups.

      • Re: (Score:2)

        by toQDuj ( 806112 )

        Thank you very much for the background and links. I was wondering how this differed from the optical tweezers already in place in labs...

    • This would be the slowest method possible of sorting isotopes. Unless you really really want just a single atom of a particular isotope floating in free space without electrodes or magnets around, there are better methods. For bulk separation you can only really go the centrifuge or gaseous diffusion route. If you have enough power available there are electromagnetic methods. If you want very small samples of ions you can use penning traps, as are used in several labs around the world for super precise
  • I want a repulsor beam. Fuck antigravity I only want to repel the ground.

    • Re: (Score:3, Funny)

      by countertrolling ( 1585477 )

      I want a repulsor beam.

      That would be a mirror. Don't look into it :-)

    • I want a repulsor beam.

      ...you mean like a rocket? Or a bigass fan?

      Or a regular laser. From TFA:

      Until now, physicists knew that the laser can push small objects. But now, researchers in China have a new experimental device, whereby the laser borounna pull objects from afar.

      (On a related note, where the hell did Google Translate pull 'borounna' from?)

      • Typically if Google Translate doesn't know how to translate a word, it will just pass the word through directly. My guess is that 'borounna' is how you say 'Bessel' in Greek, but who knows.

      • (transliterated because Slashdot apparently doesn't allow input in other languages) "boroun na" ==> "are able to"

        It's a typo in the article; basically it's saying the laser can pull objects from far away.

    • Re: (Score:2)

      by Ihmhi ( 1206036 )

      In Star Trek, tractor beams had this functionality.

      It kinda makes me wonder why they just never pushed the enemy Klingon ship into a decaying orbit or something rather than waste all those torpedoes...

      • Re: (Score:1)

        by Anonymous Coward

        In Star Trek, tractor beams had this functionality.

        It kinda makes me wonder why they just never pushed the enemy Klingon ship into a decaying orbit or something rather than waste all those torpedoes...

        Probably because the target has engines.

      • Re: (Score:2, Insightful)

        by Anonymous Coward

        You expend all that time and energy to push the opposition into a decaying orbit (which, due to simple Newtonian physics, also costs you momentum in the opposing direction and requires that you make adjustments yourself). Meanwhile, the enemy have engines and can easily compensate for your push/pull, and take a few seconds out of their not-terribly-busy schedule compensating for your attempts to throw them off, and blow your ass out of the sky. With real weapons that actually do immediate damage.

        This is k

      • It kinda makes me wonder why they just never pushed the enemy Klingon ship into a decaying orbit or something rather than waste all those torpedoes...

        I don't think a tractor beam is much of an impediment when you've got insanely powerful engines. I'd imagine the whole thing would be akin to pushing a cat down the garbage disposal, using a plastic straw.

    • I want a repulsor beam. Fuck antigravity I only want to repel the ground.

      You just reverse the polarity!

      • I want a repulsor beam. Fuck antigravity I only want to repel the ground.

        You just reverse the polarity!

        Ye canna break the laws o' physics!

  • Star Trek in our time... (Score:3, Funny)

    by turthalion ( 891782 ) on Thursday March 03, 2011 @02:29PM (#35371232) Homepage
    All we need to do is add atomic power, and bingo, nuclear bessels!

  • They always get closer until you turn them off.

  • Right now we primarily use stuff like centrifugal particle size detectors (Shimadzu for example) and the Elzone (Electrical Sensing Zone) type systems to do particle sizing for micron size diamond and other small particulates. If this process can be adapted, we have a much more precise way of setting up different sizes of particles distributions because we can pull the different size particles individually into different dispersions. The possibilities for customization of different types of particle distrib

  • I'm pretty sure there was a story just like this less than a month ago.

  • How exciting for our farming industry. Just think of the benefits!

  • So now we know how souls are pulled towards the light in near death experiences: Bessel beams.

    Who said you never learn anything new on Slashdot?

  • Tractor Beam Technology Pulling Closer

  • why no one has thought of combing this [scmec.us] with this [john-tom.com] to move particles over distance is beyond me.

  • This is like climbing a tree, and claiming you've made progress in getting to the moon.

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