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Displays Technology

Finally, a True Green Laser 274

Posted by timothy
from the greenwashing-is-everywhere dept.
dusty writes "Remember those green lasers from Star Wars? Turns out that faking green lasers has been easy for years, but making true green laser diodes has been the stuff of science fiction. Until recently, that is. Now researchers from Japan have created the world's first true green laser diode. Until now, only red and blue laser diodes were available, and now with the addition of green, new TVs and projectors that are more efficient can be produced. And if you were wondering how green lasers pointers are already produced, it is a hack that involved doubling the frequency of an infrared laser. The new true green laser diodes have much higher efficiency than the current 6%, leading many to expect big time laser display breakthroughs in the near future. Ars Technica has a well-written article on this breakthrough."
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Finally, a True Green Laser

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  • Robustness, too! (Score:5, Interesting)

    by Sockatume (732728) on Tuesday July 28, 2009 @08:09AM (#28850679)

    A laser diode is much more robust than a laser diode and the frequency-doubling package of nonlinear crystals.

  • sweet! (Score:5, Funny)

    by gEvil (beta) (945888) on Tuesday July 28, 2009 @08:10AM (#28850689)
    I can't wait to get my new RGB Laser TV(TM)! Finally all those myths about how you'll go blind from staring at the TV will be reality!
  • by ILongForDarkness (1134931) on Tuesday July 28, 2009 @08:11AM (#28850691)
    me to be the first to say: "laaayyser".
  • by Teresita (982888) <badinage1.netzero dot net> on Tuesday July 28, 2009 @08:12AM (#28850705) Homepage
    I'm sure Al Gore is thrilled with this news of green laser technology.
  • This brings us one step closer to producing a Power Ring!*

    *GL Corps version, of course. Making a Power Ring like the original Green Lantern's is just a matter of using the right kind of ancient magic.
  • Blue > Green > Red

    At this rate, the next generation games consoles will need a UV power light.

    • Re: (Score:2, Funny)

      Blue > Green > Red

      At this rate, the next generation games consoles will need a UV power light.

      I'm way ahead of the curve.. the front of my computer has a frickin' gamma ray emitter as ITS power light.

      • So? You only did that so you would turn green yourself. Green really IS better.

      • Re: (Score:3, Funny)

        by Cro Magnon (467622)

        *sigh* As usual, I'm way behind the times. I'm still using infrared, but I do plan to upgrade to the visible spectrum in the near future.

  • Fantastic (Score:5, Funny)

    by Rik Sweeney (471717) on Tuesday July 28, 2009 @08:15AM (#28850737) Homepage

    All we need now is some true frickin' sharks and we're in business.

  • Were the energy weapons in Star Wars actually called lasers? That sounds uncharacteristically unimaginative.

    • by ArcherB (796902)

      Were the energy weapons in Star Wars actually called lasers? That sounds uncharacteristically unimaginative.

      They were called "Blasters", although "Light Sabre" can sound an awful lot like Laser if you say it fast enough and they did come in green.

    • They usually referred to them as blasters, but not every time. Going into the asteroid field in The Empire Strikes Back, Han said, "That was no laser blast; something hit us!"
    • If so there is something weird going on, considering the fact that whatever they fire from their guns moves considerably slower than even a bullet, never mind light. Some sort of charged particle, maybe? If they refer to it as a laser, could that just be a common misuse of the term by the uneducated masses a long time ago in a galaxy far, far away? Or have I just had too much coffee this morning?
  • Snow Crash (Score:5, Interesting)

    by Derek Pomery (2028) on Tuesday July 28, 2009 @08:17AM (#28850755)

    Sweet. Now we just need it to draw on your eyeball.
    And not blind you.
    " Down inside the computer are three lasers - a red one, a green one, and
    a blue one. They are powerful enough to make a bright light but not powerful
    enough to burn through the back of your eyeball and broil your brain, fry
    your frontals, lase your lobes. As everyone learned in elementary school,
    these three colors of light can be combined, with different intensities, to
    produce any color that Hiro's eye is capable of seeing.
              In this way, a narrow beam of any color can be shot out of the innards
    of the computer, up through that fisheye lens, in any direction. Through the
    use of electronic mirrors inside the computer, this beam is made to sweep
    back and forth across the lenses of Hiro's goggles, in much the same way as
    the electron beam in a television paints the inner surface of the eponymous
    Tube. The resulting image hangs in space in front of Hiro's view of Reality."

    • Re: (Score:3, Informative)

      by MukiMuki (692124)

      Sweet. Now we just need it to draw on your eyeball. And not blind you.

      You mean like this [wikipedia.org]?

    • Re:Snow Crash (Score:4, Insightful)

      by Lumpy (12016) on Tuesday July 28, 2009 @09:35AM (#28852103) Homepage

      I had that image hanging in view of reality for a while.

      wearable computing and a decent HUD. Looks like sunglasses, and I'm just staring and grinning. I'm actually typing profanity at you, taking your photo, and surfing the net.

      Problem is that wearable computers are not as useful as a nice fast pocket one. my Nokia 810 and iphone kicks the crap out of any wearable I have had over the past 15 years in my personal research.

      Snow Crash tech is only useful for plugging in when you are a blob of goo at home never leaving your chair. The raging BS about logging in while riding his motorcycle will never exist as I could not even stand the speed and status info in my helmet when I used to race. Visual distractions while driving fast are not a good idea.

      Just a tidbit from a guy that has had that tech in his life, it's not all glamorous or as useful as you think. I found auditory cues to be far more useful. I switched at the end of my racing to beeps to let me know when I was at the shift point and speed ranges. It worked great.

      • Re:Snow Crash (Score:5, Interesting)

        by Daniel Dvorkin (106857) * on Tuesday July 28, 2009 @11:02AM (#28853749) Homepage Journal

        my Nokia 810 and iphone kicks the crap out of any wearable I have had over the past 15 years in my personal research.

        And your typical smartphone kicks the crap out of the typical desktop computer from a decade ago. Do you see any reason to think this trend (smaller + more powerful) won't continue?

        Snow Crash tech is only useful for plugging in when you are a blob of goo at home never leaving your chair. The raging BS about logging in while riding his motorcycle will never exist as I could not even stand the speed and status info in my helmet when I used to race.

        Fighter pilots have been using heads-up displays for almost half a century, and at this point, the view from inside a modern fighter cockpit looks more like a virtual world than it does like the real one. The same thing is happening in commercial aviation, and just starting to happen with driving and motorcycling. Maybe you didn't like your HUD, but I can almost guarantee you that future racers won't feel the same way. It's just a matter of what you're used to.

  • by Anonymous Coward on Tuesday July 28, 2009 @08:19AM (#28850779)

    Firstly, I really don't see how the solid state lasers using frequency doubling are "fake" lasers.

    Even so, outside the realm of small laser pointers, there are such a thing as gas lasers and they can produce a true green emission.

    The possible breakthrough is the production of more efficient semiconductor lasers that emit in the green range, not the production of the first "True Green Laser".

    Yeah, this is Slashdot...Whatever

    • by wigaloo (897600) on Tuesday July 28, 2009 @08:48AM (#28851173)
      Let me add to what you have said: Green beams can be obtained from solid-state infrared lasers (e.g., Nd:YAG) by using KTP or KDP crystals, which combine two photons into one (!) with twice the energy/frequency. The resulting beam is collimated and coherent - i.e., the same as the original and any other laser beam. The technique was first demonstrated in 1961 [wikipedia.org], predating this new discovery by almost half a century. Green laser diodes are most definitely interesting and useful, but to suggest that the green lasers from before were "fake" is incorrect. The new part here is having green as the fundamental frequency from a solid-state laser.
    • by Kazymyr (190114)

      Even more, there are dye-based green lasers which are tunable too. Have been around for decades.

      Also, I don't see how the existence of a (tentative) commercially available green diode laser will impact the development of "laset TVs". Unless of course you are talking of projectors.

    • Firstly, I really don't see how the solid state lasers using frequency doubling are "fake" lasers.

      From the Slashdot summary: "And if you were wondering how green lasers pointers are already produced, it is a hack that involved doubling the frequency of an infrared laser. The new true green laser diodes..."

      The intention is not to say they are fake lasers. The former green solid-state laser devices aren't just laser diodes; they are diodes plus another complicated structure. The new green laser devices are true diode lasers.

      Corrections to the Ars article:

      "Ever wonder why projector systems and televisions don't use laser illumination?"

      More important error, and my guess about the correct information: "For instance, blue laser diodes use a gallium nitride system, and figuring out how to get indium nitride to mix through the gallium nitride evenly turned out to be quite difficult."

      Full Text PDF [apex.ipap.jp] of the Applied Physics Express scientific paper. (Free)

  • True green laser? (Score:5, Informative)

    by actionbastard (1206160) on Tuesday July 28, 2009 @08:23AM (#28850835)
    Title should read "True green laser diode". 'Green' laser output has been achievable for for more than three decades with Argon ion, Krypton ion, and Copper vapor lasers. This just makes it more 'convenient' to achieve green output.
    • by lxs (131946)

      You forgot dye lasers. Those babies can be tuned to any color you want (within the range of the organic dye used of course) although CW dye lasers require powerful pump lasers and plenty of plumbing.

    • Convenient? As in portable? As in more durable? Diode pumped 1.06um YAG lasers frequency-doubled to 530nm can fit in a pen, run off two watch batteries, and take a 5g impact. Portable, cheap, durable, and even scalable to a certain extent. Argon Ion lasers output a secondary line at 514nm, but admittedly they take about 70kW input power and require 8gpm or so cooling water, but they can be really durable, supporting years of operation in poor conditions. The only real difference I see these lasers pro
  • Not fake (Score:3, Interesting)

    by avandesande (143899) on Tuesday July 28, 2009 @08:27AM (#28850893) Journal

    I am sure the guys building this laser [llnl.gov] would be more than a little pissed that you consider their laser 'fake' because it uses frequency doubling....

  • The linked wikipedia article states:

    Green laser pointers[4] appeared on the market circa 2000, and are the most common type of DPSS lasers

    Why? Whats so special about green laser pointers?

    • by physburn (1095481)
      Its the best color for taking someones eye out. Adsorbed very well by your poor red retina. Rembember not to look into Laser beam with you remaining good eye.

      ---

      Gadgets [feeddistiller.com] Feed @ Feed Distiller [feeddistiller.com]

    • The problem is that there was no known material that would act as a laser diode that emits green light -- that is, the materials which emit green light as LEDs are not suitable for emitting lasers.
      • by Candid88 (1292486)

        But why are green laser pointers more popular than red or blue ones?

        The implications of completing the RGB chart must be huge, but why are green laser pointers specifically better selling than other laser pointers? (unless ofcourse the Wikipedia article is wrong)

    • by lxs (131946)

      Green is very visible, plus the fact that 1064nm->532nm crystals were already in production for frequency doubling the output of Nb-YAG solid state lasers. (These crystals only work efficiently over a narrow range of wavelengths)

  • Every fan of I'm Sorry, I Haven't a Clue knows all about it.

    Next you'll be telling us that Japanese scientists have given Samantha a voice.

  • My eyes! (Score:3, Funny)

    by karnal (22275) on Tuesday July 28, 2009 @08:33AM (#28850971)

    The goggles do nothing!

  • There, I said it. Now we can get on with useful comments.

  • Blackadder (Score:3, Funny)

    by kyriosdelis (1100427) on Tuesday July 28, 2009 @08:56AM (#28851277)
    Oh, Edmund... can it be true? That I hold here, in my mortal hand, a nugget of purest Green?
  • by rayharris (1571543) on Tuesday July 28, 2009 @09:05AM (#28851451)
    Goodbye DLP and LCD TVs and projectors.

    Laser TVs:
    - Have higher contrast ratios (talk about true black)
    - Produce a range of colors broader than HDTV
    - Use less energy

    Unfortunately, they're still expensive. The only one that's available that I know of is the Mitsubishi Laservue. It's $7000 over at Amazon (http://www.amazon.com/dp/B001IAAD3K).

    Hopefully, this green laser will make Laser TVs more of an (afforable) reality.
  • From the article it says, "At Sumitomo Electric, they have overcome this problem by developing a GaN crystal which inhibits the efficiency drop, resulting in room temperature pulse operation of a laser diode emitting in the pure-green region at 531nm." Having worked on development of GaN blue lasers, there are a lot of challenges to getting a reliable, continuous wave (CW) diode laser that operates at this wavelength. My guess is they hammered their green diode laser with very short high power pulses just to get it to lase. So it is probably not a very useful laser if it cannot operate in CW mode.
  • Could somebody elaborate a little bit more on this?

    What is the issue with just using Indium to tune the band gap of GaN laser to the green and just having an InGaN laser?

    • Re: (Score:3, Interesting)

      Could somebody elaborate a little bit more on this?

      What is the issue with just using Indium to tune the band gap of GaN laser to the green and just having an InGaN laser?

      Never mind, from the real paper [apex.ipap.jp],531 nm Green Lasing of InGaN Based Laser Diodes on Semi-Polar {2021} Free-Standing GaN Substrates, they were using InGaN

      Lasing in pure green region around 520 nm of InGaN based laser diodes (LDs) on semi-polar {2021} free-standing GaN substrates was demonstrated under pulsed operation at room temperature. The longest lasing wavelength reached to 531 nm and typical threshold current density was 8.2 kA/cm2 for 520 nm LDs. Utilization of a novel {2021} plane enabled a fabrication of homogeneous InGaN quantum wells (QWs) even at high In composition, which is exhibited with narrower spectral widths of spontaneous emission from LDs than those on other planes. The high quality InGaN QWs on the {2021} plane advanced the realization of the green LDs. ©2009 The Japan Society of Applied Physics

      Its very tempting to actually fork out the $$ and buy that one.

  • Now I have to go out and buy a Green-Ray Player.
    .
    Thanks a lot you damn scientists!!
    .

    • Re: (Score:3, Informative)

      by irving47 (73147)

      I know you're joking, but some people won't realize that blu-ray (405nm) can store more data per disc than a green could. It can be focussed more tightly.

  • Awesome. (Score:4, Interesting)

    by Facegarden (967477) on Tuesday July 28, 2009 @12:18PM (#28855115)

    This is pretty awesome for the "toy" laser market too! Green lasers have always been pricey - I wanted to get a laser from Wicked Lasers but you can easily spend a few hundred dollars or more if you are tempted by the high powered ones. Better efficiency means its easier to make higher power, and no doped crystals means less concerns with complex alignment and cooling (the crystals get very hot!). I'd love to have a cheap high powered green laser!

    In fact, here's a diagram of a typical green laser module with all the lenses and crystals aligned.

    http://www.walshcomptech.com/repairfaq/sam/l54-101.gif [walshcomptech.com]

    It's complex, to say the least!
    -Taylor

  • would be to make a Green Lantern ring that uses green lasers controlled by Willpower. :)

  • by treeves (963993) on Tuesday July 28, 2009 @02:16PM (#28857125) Homepage Journal
    According to my handy photonic spectrum wall chart, there are green lasers already: Argon ion, Copper vapor, Nd:YAG, Xe, and HeNe, as well as, of course, tunable dye lasers. Just not laser diodes, until now.

If it's worth hacking on well, it's worth hacking on for money.

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