Scientists Create the World's First Anti-Laser

By Andrew Moseman | February 18, 2011 12:50 pm

The anti-laser—a tech with such a cool name it doesn’t need an obvious application—first came to our attention last year when Yale’s A. Douglas Stone proposed the idea. Now Stone is back with the real thing. His new paper in Science documents the world’s first anti-laser.

Conventional lasers create intense beams of light by stimulating atoms to spit out a coherent beam of light in which all the light waves march in lockstep. The crests of one wave match the crests of all the others, and troughs match up with troughs. The anti-laser does the reverse: Two perfect beams of laser light go in, and are completely absorbed. [Wired]

Anti-lasers are a bit of a funny concept, because anybody who has worn black on an August afternoon knows that absorbing light and turning it into heat isn’t a problem. But creating a device that matches the concentrated beam of a laser and traps more than 99 percent of it—essentially reversing a laser—is an engineering feat.

Whereas a laser uses mirrors to bounce light back and forth through an amplifying material to concentrate it, the anti-laser, as the name would suggest, does basically the opposite.

The difference in the anti-laser is that instead of using an amplifying material, it uses one that absorbs it — or a “loss medium.” After his research team did the math, Stone said, they decided that silicon was the best choice. The anti-laser is set up to split a single laser beam into two and direct the two beams to head toward each other, meeting at the paper-thin silicon wafer. The light’s waves are precisely tuned to interlock with each other and become trapped. They then dissipate into heat. [Los Angeles Times]

The fact that Stone’s team created a anti-laser so quickly after theorizing it isn’t the only surprise. Another is that nobody had thought to do it until so recently.

The reversal experiment is exciting because nobody had thought of it before, says Marin Soljačić, a physicist at the Massachusetts Institute of Technology in Cambridge. “It is surprising to have something so new and quite fundamental discovered in such a mature field,” he says. [Nature]

The creators aren’t sure exactly what to do with this new toy. But as the Los Angeles Times points out, the same was true of the laser upon its invention in the 1960s, and now supermarkets and Lasik clinics couldn’t live without it.

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Image: Science / AAAS

CATEGORIZED UNDER: Physics & Math, Technology, Top Posts
  • raja reddy

    i am happy to go through a item Scientists build 1st antilaser published in india local darily tow 19-02-2011. i prepared a paper “a surmise oon photon” a decade ago and sent various generals for publication but non accecpted in for reason or another. i have physical entriprision of the photon as a doublet similar to a binary star. this is based on the process of generation of gama rays when electron interesx with positron i send the full paper if your email id is given
    thanking you,

  • Katharine

    Why, protect things FROM lasers, of course!

  • MensaJeff

    Looks like a cheap and easy way to transfer/deliver energy from one place to another…this is the kind of thing that turns out to be the long-sought answer to a very particular problem. I can’t wait to see where it pops up.

  • person

    Anti-laser rocket uses heat to fire a propellant for thrust using ground based lasers.

  • Suncat2000

    It can actually be used like a “sponge” or buffer for lasers used in manufacturing. There may be cheaper ways to accomplish it, but having an anti-laser device behind a piece of material being cut by a laser would be a safeguard against, well, having no material in place to cut. Instead of burning through the mounting surface, the energy could be safely dissipated, causing no damage.

    I don’t know if that’s what Katharine meant, but that’s my idea.

  • Save The Sattelites

    I believe defence establishments and satellite companies would be interested in this technology. This would be a likely help to protect satellites from warfare technology that certain countries are aggressively pursuing as well as potentially delivering a striking blow to laser guided missiles. Would be interesting to see if this would indeed be something that the US defence dept will pursue to lock away.

  • Dr. Evil

    My sharks need to protect themselves from other-shark misfires…

  • Iman Azol

    The need to precisely split the beam and use it to cancel itself means it won’t work for defense or screening. Its purpose is energy transfer.

  • Joey B.

    I’m curious if this can be used in any sort of culinary arts. Instead of electric or gas, we could have laser stoves. Of course, this makes me wonder just how much heat is dissapated.

  • Jeff Wright

    True enough. Optical computing might also be another application. I also wonder if there might be applications with regards to programmable matter

    Using laser tweezers to manipulate very small items (if not using this exact method, perhaps off angle a bit to get motion) could be very useful. What I want to see is someone make a nanotube of a continuous length, not just this clingy stuff they pull off bars that are just stuck together. MEMS could be microlooms and some type of laser or other ways to manipulate at the very small could allow really strong cables.

    Now some of you might remember SCIENCE Illustrated’s current issue about needing a large laser for a spacecraft of some kind:

    Now seeing that an asteroid might be coaxed into a star to form a natural laser, there might now be a way to transfer a great deal of the sun’s energy into a device in a single go. Then too, getting everything to line up just right would be a headache. This all seems good for lab only usage or in some consumer product of some kind.

    For some reason, seeing the two beams meet and cancel reminded me of a line in ATHF

    Two men enter, no man leaves–rated R

  • Iain

    In every energy exchange there will be losses.
    Using laser to transmit energy over a distance in atmosphere is impractical. Scatter and absorption by particulate would be huge.
    There may be some hope as a rocket propellant if you can get sufficient heat transfer from the material to atmosphere, (simple mirrors may work better).
    As a defense tool, it’s usefulness is severely limited in that they need to precisely split the beam…
    As a stove? There wasn’t any data about losses, so how do you compare the resistant coil versus the infra red versus the magnetic induction versus the anti laser?
    As for heat dissipation, energy out < energy in. So that micro-watt pointer laser isn't going to boil water for your tea no matter how long you wait.

  • Darth Vader

    Interesting… full protection from laser bolts you say…

  • anze

    Hehe, funny, I had the same idea during a physics lecture last year, asked a professor about it and he said it was possible, but then didnt research it further. I want a paper published in Science too :D.

  • DinoBoy

    Isn’t there some application of this theory for solar panels? Absorbing the suns rays and coverting it into energy? Maybe I missed the point…

  • Green Power

    Deep within the Earth use heat enegry to excite a laser. The drill rig drill piping could be used as a light tube and at the surface an anti-laser to capture the heat energy to generate electricity. Completely green power that is available 24/7.

  • Dan

    > Quote: Looks like a cheap and easy way to transfer/deliver energy from one place to another…this is the kind of thing that turns out to be the long-sought answer to a very particular problem. I can’t wait to see where it pops up.

    Except that heat is the last form you want energy to take. Heat has the highest entropy and therefore is least usable. You’d be better off just sending the energy as microwaves or electricity.

  • Brian Too

    Isn’t this kinda anti-climactic? I mean shine a laser on any non-reflective surface. What do you get? Heat. Here they’ve discovered a way to convert a laser to (tada!) heat.

    Maybe there’s more control or better conversion or something. Right now it just seems like a fancy way to do what everyone already does zillions of times a day. Without even trying.

    Convert the laser directly back to electricity with no heat losses. Now maybe you’ve got something.

  • Jeff Wright

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