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Science Technology

Scientists Invent World's First Anti-Laser 241

Posted by timothy from the what-about-my-anti-anti-anti-anti-anti-laser? dept.
Velcroman1 writes "Two scientists at Yale University have built the laser's first doppelganger: the anti-laser. While a conventional laser emits a constant beam of light in one direction, the anti-laser simply does the opposite. It takes that same steady light stream and interacts with it in such a way that it absorbs and cancels out the light. And scientists hope the strange creation could help the fight against cancer. A. Douglas Stone, one of the two researchers behind the project, said he came up with the idea for a 'nega-laser' when working with equations for a random laser with his partner in crime, Hui Cao. 'I figured, if we just somehow illuminated the cavity, and replaced the gain medium with something that tends to absorb light, we could essentially reverse the process,' Stone said. Oh, that makes sense."
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Scientists Invent World's First Anti-Laser More

Scientists Invent World's First Anti-Laser

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  • Challenge for biologists: (Score:4, Funny)

    by Anonymous Coward on Thursday February 17, 2011 @05:25PM (#35237184)

    Now it's up to the biologists to create anti-sharks

  • Beam of darkness? (Score:5, Funny)

    by bluefoxlucid ( 723572 ) on Thursday February 17, 2011 @05:26PM (#35237208) Homepage Journal
    It shoots a coherent beam of darkness!

    • Re: (Score:2)

      by Gilmoure ( 18428 )

      I was thinking it made a non-coherent, spherical light field. That would actually be useful.

    • Re: (Score:3, Informative)

      by irp ( 260932 )

      It shoots a coherent beam of darkness!

      In quantum optics when you need to silence the vacuum noise from the "dark" port of a beam splitter. You make a squeezed light source, point it at the dark port and decrease the power to just *below* laser threshold. It does not emit light, but it still squeezes the vacuum state along the path of the beam-without-light, i.e. a "coherent beam of darkness"...

      I've always found that phenomena slightly eerie... :-)

  • Yes, Dr. Scott... (Score:3)

    by emurphy42 ( 631808 ) on Thursday February 17, 2011 @05:27PM (#35237216) Homepage
    ...an anti-laser capable of emitting a beam of pure anti-anti-matter.
    • I'm pretty sure a device that took electricity and emitted a stream of matter would be damn interesting.

  • Oh great. (Score:5, Funny)

    by towelie-ban ( 1234530 ) on Thursday February 17, 2011 @05:28PM (#35237236)
    Now they'll create freaking anti-sharks to attach these to.

  • scientists? (Score:3)

    by bugi ( 8479 ) on Thursday February 17, 2011 @05:35PM (#35237326)

    I'm shocked. I would've assumed it was priests, or maybe economists.

    • Re: (Score:2)

      by rsborg ( 111459 )

      I'm shocked. I would've assumed it was priests, or maybe economists.

      There's really no difference between the two.

  • ... yet I can't help thinking that it's akin to the classic black body. Light hits it and is absorbed. I assume the energy is re-emitted from said anti-laser in the form of heat or some-such.

    No doubt there's more to it than this. But TFA isn't clear.

    • But you didn't RTFC from the diagram, "In the anti-laser, incoming light waves are trapped in a cavity where they bounce back and forth until they are eventually absorbed. Their energy is dissipated as heat."

      • Re: (Score:2)

        by jfengel ( 409917 )

        Heat... what? Infrared radiation? Molecular motion?

        I'm sure this is an important and interesting advance, but I found that description singularly uninformative.

        • Are you serious? It says heat. Yes infrared radiation is emitted. Yes there is more molecular motion. That's what heat does, do you really need the article to spell it out?

      • All energy is eventually dissipated as heat.

    • Yes, there's more to it than you think: the device in question is a coherent absorber (just as a laser would coherently emit electromagnetic radiations), so it's fundamentally different from a black body, which abides to Planck's law of blackbody radiation.

    • Re: (Score:3)

      by Andy Dodd ( 701 )

      The impression I get is that they have managed to achieve an ideal absorber for a specific frequency.

      That's what a classic black body is, but there is nothing in the real world that behaves this way.

      • Re: (Score:2)

        by jfengel ( 409917 )

        What happens to other frequencies? Are they transmitted? Absorbed? Reflected?

        If they're absorbed, what's special about this frequency? Is the heat radiated from it in some other way than as a standard blackbody radiation?

      • A classic black body absorbs all frequencies. This is a very specific frequency absorption. No idea what it'd be useful for, but it's still a technically impressive capability that wasn't available before

        • Re: (Score:2)

          by c0lo ( 1497653 )

          A classic black body absorbs all frequencies. This is a very specific frequency absorption. No idea what it'd be useful for, but it's still a technically impressive capability that wasn't available before

          Like a ballpoint pen able to function in zero-g?

        • Re: (Score:2)

          by Dunbal ( 464142 ) *

          A classic black body absorbs all frequencies

          With the other minor technical detail that it doesn't exist. But when has reality ever stopped physicists? Give me a lever of infinite length and an immovable place to stand...

    • Re:OK - so I RTFA... (Score:5, Informative)

      by IICV ( 652597 ) on Thursday February 17, 2011 @06:06PM (#35237740)

      All they really needed to say was that it's the time-reversed counterpart of a laser. Calling it an "anti-laser" makes it sound like it shoots out a beam of darkness or something like that (which could be cool, but physically impossible).

      Why this is neat is that, because it's the reverse of a laser, it'll absorb some frequencies almost perfectly while ignoring others. The reason why they said this would work for cancer, for instance, is that you could embed some of these dudes in the cancer (there's techniques for that, I have no idea how they work) and then bombard them with a laser frequency that normally passes harmlessly through humans. Areas without these reverse-lasers will be unaffected, but areas with them will get really hot, killing the cancer. We use similar techniques already (with I think gold, I'm not quite sure) in order to localize radiotherapy, but I believe that the radiation used in the current methods still kills a lot of normal cells on its own.

      • Re:OK - so I RTFA... (Score:4, Insightful)

        by Colonel Korn ( 1258968 ) on Thursday February 17, 2011 @06:12PM (#35237802)

        All they really needed to say was that it's the time-reversed counterpart of a laser. Calling it an "anti-laser" makes it sound like it shoots out a beam of darkness or something like that (which could be cool, but physically impossible).

        Why this is neat is that, because it's the reverse of a laser, it'll absorb some frequencies almost perfectly while ignoring others. The reason why they said this would work for cancer, for instance, is that you could embed some of these dudes in the cancer (there's techniques for that, I have no idea how they work) and then bombard them with a laser frequency that normally passes harmlessly through humans. Areas without these reverse-lasers will be unaffected, but areas with them will get really hot, killing the cancer. We use similar techniques already (with I think gold, I'm not quite sure) in order to localize radiotherapy, but I believe that the radiation used in the current methods still kills a lot of normal cells on its own.

        You win. Mods, please get the parent to +5 Informative. It's clearly the best post on the story.

        • All they really needed to say was that it's the time-reversed counterpart of a laser. Calling it an "anti-laser" makes it sound like it shoots out a beam of darkness or something like that

          A time-reversed proton is an anti-proton. A time reversed electron is an anti-electron. This is just keeping with the pattern...

      • Calling it an "anti-laser" makes it sound like it shoots out a beam of darkness or something like that (which could be cool, but physically impossible).

        Not quite impossible. Since a laser is coherent light, it should theoretically be possible to produce a beam that is phase-shifted so as to cancel out another laser of the same frequency. That wouldn't be a "beam of darkness" in the general sense, but it could null out the other laser. It would probably take a massive amount of real-time DSP computations to make it even partially work.

  • Can you install this near the cockpit of planes, making them immune to the dreaded blinding green laser attack? Or for that matter, make something immune to laser guided missiles?

  • Its called a D.A.S.A.R. (Score:4, Funny)

    by scharkalvin ( 72228 ) on Thursday February 17, 2011 @05:44PM (#35237454) Homepage

    That's "Darkness Amplification by Stimulated Absorbance of Radiation"

  • Scientist: We have an amazing toy! It does weird stuff, but nothing useful. In fact it's so weird, we don't even know what's happening. Who knows, once we figure it out, we might find that it is similar to radiation therapy used today to combat cancer.

    Reporter: The scientists believe that someday it could be used in our fight against cancer

    Editor: hmm... it's not really that big of a story. The only thing that makes it interesting enough to print is the bit about cancer.

    Final printed version: It CURES

    • That's how academic funding works. If it doesn't kill people or cure cancer, you're basically begging on the street.

  • "Doppelganger"? (Score:4, Informative)

    by Artifice_Eternity ( 306661 ) on Thursday February 17, 2011 @05:47PM (#35237508) Homepage

    Two scientists at Yale University have built the laser's first doppelganger: the anti-laser.

    I do not think this word means what you think it means. [wikipedia.org]

    • Re:"Doppelganger"? (Score:5, Funny)

      by ColdWetDog ( 752185 ) on Thursday February 17, 2011 @06:04PM (#35237700) Homepage

      I do not think this word means what you think it means.

      That's OK, the entire article doesn't mean what the reporter thought it meant.

    • Re:"Doppelganger"? (Score:4, Insightful)

      by insertwackynamehere ( 891357 ) on Thursday February 17, 2011 @06:20PM (#35237920) Journal

      Um "A doppelgänger (pronounced [dplg] ( listen)) is a tangible double of a living person in fiction, folklore, and popular culture that typically represents evil. In the vernacular, the word doppelgänger has come to refer (as in German "doppelt(e)") to any double or look-alike of a person." from your link right there it clearly is being used in the "evil twin" sense

    • Re: (Score:2)

      by HiThere ( 15173 )

      I a way it does. In traditional usage a doppelganger was not only identical to you, but if you met your doppelganger, you would both die.

      It's a bit of a stretch, but you could say that the light of the laser is "killed" by meeting it's doppelganger, i.e., the opposite of the conditions that gave it birth. (Mind you, I agree that it's quite a stretch.)

  • A laser receiver, not an anti-laser. (Score:3)

    by Fieryphoenix ( 1161565 ) on Thursday February 17, 2011 @06:00PM (#35237664)
    An anti-laser would emit light in every direction except for a tightly focused beam.
    • And an anti-proton is a proton which exists everywhere but one particular point. Get real. The term "anti" has no such specific meaning.
  • 1) Anti-laser

    2) ?

    3) Profit!

  • to be used in optical computers? (Score:3, Informative)

    by Anonymous Coward on Thursday February 17, 2011 @06:17PM (#35237860)

    BBC article on the same subject talks only about using in optical computers.

    http://www.bbc.co.uk/news/technology-12453893

  • Why are we getting ours news from Fox? For every concrete nit-picky criticism I can make about the article (improper use of the word "doppelganger", the strangely "compressed" quotation at the end) there are some serious conceptual issues with the article as well. I'm not convinced the author understands half of what's going on. I've gotten the distant impression from the interviews that this is a device that takes in a laser light and dissipates the light into heat, but the article seems to be implying any

    • Re:Fox News? (Score:5, Informative)

      by IICV ( 652597 ) on Thursday February 17, 2011 @06:40PM (#35238206)

      The article is absolute shit, but if you ignore everything the journalist wrote and just read what the physicist said you can get an idea of how this works.

      Basically, it's the reverse of a laser; the physicist meant "anti-laser" as in "anti-matter" (because if you reverse the flow of time, anti-matter looks like regular matter).

      Normal lasers take power in and emit light at a specific frequency; this thing takes light in at a specific frequency and emits power. In other words, if you take a video of a laser and play it backwards, that's this thing.

      • Re: (Score:2)

        by Alsee ( 515537 )

        if you take a video of a laser and play it backward

        Little known fact: Lasers are tools of the Devil. They generate hidden satanic images that can only be seen when you play the video backwards.

        -

    • Why are we getting ours news from Fox?

      Fox News reported something the mainstream media didn't.

      You anti-Foxers have this infinite loop problem:

      1) Fox News reports something no other source does;
      2) Libs yell "LA LA LA I CAN'T HEAR YOU FOX IS BIASED!" and remain ignorant of the story;
      3) Rinse and repeat.

      I can name numerous stories the MSM ignores, and only Fox reports, but you wouldn't want to hear about it because Fox reported it!

      And your whole anti-science thing by Fox viewers is just BS generalization. Sure, there are some creatio

      • A quick google shows Reuters picked it up, Popular Science, and the BBC.

        Of course Fox is biased...just like any other media source. The key, for both sides, is to filter reports from the different sources appropriately, and the problem is to insure that the filter doesn't remove too much or color the information too much.

        sr

    • I'm not a fan of Fox, and I see some of your criticisms, but don't think it's that big of a deal.

      Doing a speed read of tfa, I don't get any undertone about "death of us all". Not being interested in the techie aspects of this, I found that I got the gist of it adequately.

      sr

  • ... just heaved a huge sigh of relief.

  • This is just constructive or destructive interference of two beams of light, no different than a resonant-cavity photodiode, which has existed for 20 years. Lasing, if you recall, is stimulated emission, represented by one of Einstein's coefficients. The opposite physical process, which is the opposite Einstein coefficient, is absorption, which is always stimulated (there's no such thing as spontaneous absorption). We've long known about "anti-lasing"--it's called absorption.

    Nothing to see here, move along.

  • I'm TOTALLY going to $&*# with the cat's head!

  • While a conventional laser emits a constant beam of light in one direction, the anti-laser simply does the opposite. It takes that same steady light stream

    and emits it in the other direction.

  • You will be assimilated.

    Can this technology be adapted as a defense used by a cyborg alien race, by any chance?

  • To create a laser, you need to excite the atoms in the medium. So with an anti-laser, does that mean the atoms are depressed? Maybe they need a little atomic prozaic.

  • Holy shit, did he just invert the polarity?

  • Replacement for electrical power xmission lines (Score:3, Insightful)

    by American Patent Guy ( 653432 ) on Thursday February 17, 2011 @07:57PM (#35239128) Homepage
    If these guys have come up with something that will scale up to megawatt powers, this could spell the end of overhead power lines. It could power anything line-of-sight, including satellites. It could also transmit solar power harvested from space to the earth. Laser light can be focused tightly onto a target, unlike microwaves or radio-based radiation. This could be very efficient...

  • came up with the idea for a "nega-laser" when working with equations for a random laser with his partner in crime

    Wow, some people are really taking their DC Universe Online character builds seriously. Can I join their guild?

  • Sooo... lightsaber anyone?

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