Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Science Technology

Scientists Invent World's First Anti-Laser 241

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."
This discussion has been archived. No new comments can be posted.

Scientists Invent World's First Anti-Laser

Comments Filter:
  • "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: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.

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

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


  • 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:prior art (Score:2, Informative)

    by Dcnjoe60 ( 682885 ) on Thursday February 17, 2011 @07:19PM (#35238748)

    Actually, the OP is correct. the matte black paint does absorb all of the light. If you look at the other side of what ever it is painted on, you no longer see the laser light. It doesn't even have to be matte black paint. It can be any color paint you want.

    Proof of concept: Take a piece of poster board and paint it whatever opaque color you want. Place a light meter on the unpainted side. Shine a laser on the painted side and record the change in light as detected by the meter. If there isn't any, then the painted poster board absorbed all of the laser light.

    When I used to do black and white photography, I used to use nega-light all the time when loading film into cartridges. The difference was that instead of black poster board, I used a black cloth sack. It effectively absorbed all of the visible light that hit it. It was much more impressive than only being able to absorb one specific wavelength of light at a time.

  • by Bigjeff5 ( 1143585 ) on Thursday February 17, 2011 @10:32PM (#35240308)

    Guess what - absorbing light isn't particularly difficult.

    Guess what, absorbing light perfectly is.


  • Re:Beam of darkness? (Score:3, Informative)

    by irp ( 260932 ) on Friday February 18, 2011 @06:22AM (#35241934)

    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... :-)

I THINK MAN INVENTED THE CAR by instinct. -- Jack Handley, The New Mexican, 1988.