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Shark Technology

South African Research Team Creates World's First Digital Laser 81

Posted by samzenpus
from the better-focus dept.
smi.james.th writes in with news about new laser technology developed in South Africa. "The Council for Scientific and Industrial Research (CSIR) announced in Pretoria on Tuesday that it had developed the world's first digital laser. 'I am always very cautious about using the term "breakthrough",' noted Science and Technology Minister Derek Hanekom. 'We scrutinized this very carefully before we said that this is really new! South African scientists are once again making noteworthy contributions to the world.'... A normal laser contains two mirrors, opposed to each other and at opposite ends of the instrument. One is highly reflective and the other is a curved, partially reflective mirror. In the digital laser, the curved mirror is replaced by a liquid crystal display (LCD) system. The LCD is connected to a computer and monitor."
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South African Research Team Creates World's First Digital Laser

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  • by mcgrew (92797) * on Wednesday September 18, 2013 @07:12PM (#44889061) Homepage Journal

    Researchers use the computer to specify the laser beam shape they require and to programme it into the LCD. By this means, one laser can swiftly produce many different beam shapes. Previously, changing the shape of a laser beam required physically replacing the curved mirror in the laser. As the mirror has to be carefully aligned, this is a time consuming process.

    • by mcgrew (92797) *

      Oops, I forgot the blockquotes. That was from TFA (not a good FA IMO)

    • by hedwards (940851) on Wednesday September 18, 2013 @07:19PM (#44889139)

      I fail to see how that's digital, but it's a cool advancement none the less. The beam itself is still just a laser beam.

      • by TechyImmigrant (175943) on Wednesday September 18, 2013 @08:18PM (#44889479) Journal

        Maybe it has fingers.

      • by mcgrew (92797) * on Wednesday September 18, 2013 @11:15PM (#44890415) Homepage Journal

        I fail to see how that's digital

        An English major wrote it. It uses a computer-controlled LCD instead of a curved mirror. There are benefits, TFA isn't very good at explaining them because the guy who wrote the article either didn't understand the concepts or really sucks at communicating them. You really have to look hard through the overabundance of redundant marketspeak verbiage to grok it.

        • Re: (Score:3, Insightful)

          by Em Adespoton (792954)

          I fail to see how that's digital

          An English major wrote it. It uses a computer-controlled LCD instead of a curved mirror. There are benefits, TFA isn't very good at explaining them because the guy who wrote the article either didn't understand the concepts or really sucks at communicating them. You really have to look hard through the overabundance of redundant marketspeak verbiage to grok it.

          I doubt an English major wrote it -- it looks an awful lot like a Communications major wrote it; an English major wouldn't use an overabundance of redundant marketspeak, but would instead make all sorts of obscure references in fairly terse but accurate English.

        • "Digital laser" is what the leader of the research group has dubbed it, and he's not the first optics researcher to call his invention a digital laser. "English major". Jesus Christ.

          http://ntww1.csir.co.za/plsql/ptl0002/PTL0002_PGE157_MEDIA_REL?MEDIA_RELEASE_NO=7525990 [csir.co.za]

      • I fail to see how that's digital, but it's a cool advancement none the less. The beam itself is still just a laser beam.

        There's a lot of misuse of the word "digital". It ultimately just means something which comes in quantified pieces. Not necessarily even electronic or computerized. It is a cool word for marketing though...

      • by khundeck (265426)

        I fail to see how that's digital ...

        Well you said it not me. :-) ["fail"] It's pretty obvious FTA. Maybe you're subtly suggesting that lasers have always been digital??? I don't know enough about it.

        FTA: A 'laser beam' apparently has a few components. The "analogue" way - two mirrors on each end of the device. The "digital" way - replace the one curved mirror with an LCD THAT HOOKS UP TO A COMPUTER. The computer controls the LCD (orientation of the liquid crystals) and ultimately affects the laser shape. I'm amazed that they can use

        • by hedwards (940851)

          My parents can hook their record player up to a computer, does that mean that the record player is digital?

          The fact is that the laser is just a laser, they've added some cool technology to it, but it's still the same laser that it always was. Using digital controls doesn't make for a digital laser, there've been digital controls for years.

    • by girlintraining (1395911) on Wednesday September 18, 2013 @07:25PM (#44889185)

      As the mirror has to be carefully aligned, this is a time consuming process.

      This has already been partially solved using nano mirrors -- basically the rear reflector is a pile of mirrors that each have independent servos. It's nano tech. Like I said... early stages.

    • by ackthpt (218170) on Wednesday September 18, 2013 @07:43PM (#44889279) Homepage Journal

      Researchers use the computer to specify the laser beam shape they require and to programme it into the LCD. By this means, one laser can swiftly produce many different beam shapes. Previously, changing the shape of a laser beam required physically replacing the curved mirror in the laser. As the mirror has to be carefully aligned, this is a time consuming process.

      This will be of immense benefit to mankind.

      Once I fit one of these in the back of my car it will spell out messages for drivers following me to read; e.g. Your Turn Signal Has Been On For The Past 3 Miles.

      • by PopeRatzo (965947)

        Once I fit one of these in the back of my car it will spell out messages for drivers following me to read; e.g. Your Turn Signal Has Been On For The Past 3 Miles.

        "Spell out messages"? Hell, I want one that will vaporize the guy that's been tailgating me since the St Louis turnoff.

        • by ajlitt (19055)

          Can it write "CHA"?

        • by mcgrew (92797) *

          Their lasers aren't that powerful yet and anyway, they only do infrared so far so good luck reading the messages.

      • Researchers use the computer to specify the laser beam shape they require and to programme it into the LCD. By this means, one laser can swiftly produce many different beam shapes. Previously, changing the shape of a laser beam required physically replacing the curved mirror in the laser. As the mirror has to be carefully aligned, this is a time consuming process.

        This will be of immense benefit to mankind.

        Once I fit one of these in the back of my car it will spell out messages for drivers following me to read; e.g. Your Turn Signal Has Been On For The Past 3 Miles.

        And here I thought you were going to say "Once I fit one of these on the back of my shark...."

      • Ooooh I gotta patent inverting the image so people can read it in their mirrors.

    • by Ungrounded Lightning (62228) on Wednesday September 18, 2013 @07:50PM (#44889329) Journal

      My impression is that, because the mirror is "replaced" with the LCD, the LCD is inside the cavity, with each pixel modulating either the Q or the polarization of a particular chunk of the cross-section of the cavity. This amounts to adjusting the gain of the various modes of the cavity and thus switching which one(s) oscillate and consume the energy from the amplifier in the cavity.

      Though the modes that are selected would not be mapped one-to-one onto the pixels, , you can control a lot of modes with the ciquid crystal display - probably all of them available, or up to the number of pixels in the liquid crystal device.

      You can also switch them as fast as the liquid crystal switches. With modern drivers (which remember the previous state of the liquid crystal in each pixel and temporarily overdrive those that must change more in order to switch them rapidly, rather than just letting them settle passively into the new state) you can switch it at 60 Hz or better.

      You might use holographic techniques to change the angle of the beam, or emit a number of beams of various intensities in various directions. Result: Scanning and image formation without moving parts (other than the molecules in the display).

      I think the computation to turn it into a (one-color) projector would be pretty much a straight 2-D FFT times a nonliinear tweak to deal with energy-stealing among modes.

      I'd like to see versions of this with array-of-Kerr-cells in place of the liquid crystal device (for more rapid modulation, at the cost of high voltage drivers), or digital light processors for the mirrors (though the latter are more on/off than continuously adjustable so they might be more limited on what beams they can form).

      • by Sarten-X (1102295)

        I think the computation to turn it into a (one-color) projector would be pretty much a straight 2-D FFT times a nonliinear tweak to deal with energy-stealing among modes.

        And that means a full-color high-quality laser projector is just over 3x as expensive, but still feasible. I, for one, am excited.

        • by mcgrew (92797) *

          Don't get too excited yet, so far it can only do infrared. What surprised me was that pixel density on LCDs was so good. We could have digital holograms right now using good old fashioned 1970s mirrored lasers in the displays.

          I don't know why nobody's done it.

      • To run "holographic" displays, don't you need to be able to control the liquid crystal shutter down to at least the wavelength of the light being controlled? After all, a hologram is merely an interference pattern, and the interference pattern would be on that scale. I may be out of the loop, but I don't think we have nano-scale liquid crystal tech yet.
        • Not at all. The size (spacing) of the pixels relative to the wavelength limits the angle through which you can (first-order) diffract the beam,

          A hologram of a scene where only a small region, very near the spot the reference beam is aimed at, i.e. one that leaves most of the light nearly parallel to the reference beam on reconstruction, is a very low-resolution, big-blobby thing.

      • by goombah99 (560566)

        I'd like to see versions of this with array-of-Kerr-cells in place of the liquid crystal device (for more rapid modulation, at the cost of high voltage drivers), or digital light processors for the mirrors (though the latter are more on/off than continuously adjustable so they might be more limited on what beams they can form).

        your wish is my command:
        http://www.ncbi.nlm.nih.gov/pubmed/18319825 [nih.gov]

      • by thygate (1590197)
        60 Hz would be terrible. Let's imagine they can IQ modulate 64 symbols (6 bits per symbol) with a samplerate of 60 Hz, that gets you 6 * 30 (Nyquist) = 180 bits per second.
        • 60 Hz would be terrible. Let's imagine they can IQ modulate 64 symbols (6 bits per symbol) with a samplerate of 60 Hz, that gets you 6 * 30 (Nyquist) = 180 bits per second.

          That's per pixel in the modulator. Now multiply by the number of (mega) pixels.

          The modulator is essentially the guts of an LCD display so you get the same bandwidth as the video image it could display. What's new is:
          - You're modulating the(many) modes of the cavity itself, rather than shaping the beam after it emerges.
          -

    • by Osgeld (1900440)

      Thank you, note to slashdot, you could replace the 2nd and 3rd sentence in your pretty much worthless summary with the ones provided above and turned it into something that had a fucking point.

    • by citizenr (871508)

      Previously, changing the shape of a laser beam required physically replacing the curved mirror in the laser. As the mirror has to be carefully aligned, this is a time consuming process.

      But picking crystal for your lightsabe^^^laser is a rite of passage!

    • by msauve (701917)
      Thanks for that. This seems to be a "digital LASER" only in relation to a very specific quality. It is certainly not the "world's first digital LASER." There are millions of LASERs which operate digitally already in common use - many (most?) Ethernet fiber optic transceivers use LASERs which are digitally modulated.

      (much 1000base is LASER, AFAIK all 10Gbase is LASER)
    • here's the patent from 2000
      https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US6031852.pdf [google.com]

      instead of an LCD, which are slow, the inventors used an accoustoptic modulator as the pattern former. Those are fast. In fact they are so fast they could also use the pattern former to sweep the wavelength in real time or q switch the laser.

    • by LoRdTAW (99712)

      I would assume YMMV but the rear mirrors in industrial lasers are quite easy to tune. I work at a laser welding shop where we use lamp pumped pulsed Nd:YAG lasers. Rear mirror alignment is done manually using two screws and takes about 20-30 minutes thanks to the built in tuning meter. You set a pulse rate and width (eg 20Hz, each pulse 2ms long) and watch the power meter. You start with a number that gives you 10 watts and then tune until you can't get the power any higher(you now might have 15W. Then you

  • by Anonymous Coward on Wednesday September 18, 2013 @07:16PM (#44889111)

    Unfortunately it's half as effective.

    See, the 1s have sharp edges and really abrade the material, but the 0s just roll right off.

  • by Anonymous Coward on Wednesday September 18, 2013 @07:18PM (#44889129)

    Is digital sharks

    • I was under the impression that nonpracticing entities specializing in asserting broad patents of questionable quality had the "sharks" part covered.
  • Spatial light modulators to shape laser beams were big stuff 25 years ago but I haven't seen mention of them for a very long time. Is there really anything new in this work or is it something (nearly) forgotten being rediscovered?

  • Solve the analog shark problem, we will be all set! Sounds like a good darpa project.
  • I completely just read that as Petoria, and was expecting Joehio to be developing the sharks.

  • There already has been something similar in Soviet Russia before 1990 but it was analog, not digital.

    Russians have invented the laser TV projector where the lasing crystal was excited with scanning electron beam. Of course, it was purely experimental, monochrome and needed liquid nitrogen cooling but it worked spectacularly. The photo has been published in Russian popular RADIO magazine.

  • South African Research Team Creates World's Frikken Digital Laser

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