5351539
story
Comments: 274 +- Technology: Finally, a True Green Laser on Tuesday July 28 2009, @08:08AM
background: url(//a.fsdn.com/sd/topics/topicmonitors.gif); width:52px; height:53px;
displays
background: url(//a.fsdn.com/sd/topics/topictech2.gif); width:60px; height:80px;
technology
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."
Related Stories
A great many people think they are thinking when they are merely
rearranging their prejudices.
-- William James
All trademarks and copyrights on this page are owned by their respective owners. Comments are owned by the Poster. The Rest © 1997-2010 Geeknet, Inc.
Robustness, too! (Score:5, Interesting)
A laser diode is much more robust than a laser diode and the frequency-doubling package of nonlinear crystals.
Re:Robustness, too! (Score:5, Funny)
A laser diode is much more robust than a laser diode
*head explodes*
Parent
Re:Robustness, too! (Score:5, Informative)
*head explodes*
"A laser diode is much more robust than (a laser diode and the frequency-doubling package of nonlinear crystals).
Parent
Re:Robustness, too! (Score:5, Insightful)
Parent
Re:Robustness, too! (Score:5, Funny)
It's not illiteracy, it's attention deficit. Why read the whole sentence when you can just read
*head explodes*
Parent
Re:Robustness, too! (Score:5, Funny)
*head
*head explodes*
*head explodes*
*head explodes*
*head explodes*
ok seriously, you guys? Can we?
You make my head explode every time you talk to me.
And when your commenting, its like a lobotomy.
You think that I am dumb, wont you just explain to me?
I need a dictionary or car analogy.
Parent
Re: (Score:3, Informative)
Laser projectors, dude!
Great contrast, tremendous color gamut, and they can project from any off angle since there's no real focusing issue.
Granted, there's more bugs to work out, but the lack of a cheap green laser was the probably the biggest issue holding the technology back.
Re:White laser lights? (Score:5, Funny)
Parent
Re:Robustness, too! (Score:5, Funny)
(laser diode).robustness > ( (laser diode)+(frequency-doubling package of nonlinear crystals) ).robustness
Better?
Parent
Re:Robustness, too! (Score:5, Funny)
expected ;
Parent
Re:Robustness, too! (Score:5, Funny)
it was Python, you insensitive clod!
Parent
Re:Robustness, too! (Score:5, Funny)
Parent
Re:Robustness, too! (Score:5, Funny)
frequency-doubling package of nonlinear crystals
^ frequency not defined
^ doubling not defined
^ the reserved word "package" cannot be used in this context
^ the reserved word "of" cannot be used in this context
^ the reserved word "nonlinear" cannot be used in this context
^ chamber in use, dilithium crystals cannot be accessed at this time
^ expected ;
Parent
Re:Robustness, too! (Score:5, Funny)
Parent
Re:Robustness, too! (Score:5, Funny)
A laser diode is much more robust than a laser diode and the frequency-doubling package of nonlinear crystals.
How waterproof are they? I've a few military applications regarding applying said diodes to a member of the selachimorpha order. Attached between it's snout and first dorsal fin would be the ideal configuration.
Parent
Re:Robustness, too! (Score:5, Funny)
Parent
Re: (Score:3, Funny)
Would you settle for a member of the perciformes order with an attitude?
Provided they're one of the Moronidae, sure.
Re: (Score:3, Funny)
Geneva Accords, 32 Nations Summit, April 2039, Section 329, Paragraph 27.
Dave
sweet! (Score:5, Funny)
Re:sweet! (Score:5, Funny)
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!
Warning: don't watch TV with remaining eye.
Parent
Re:sweet! (Score:4, Insightful)
I don't think you need lasers to do this. Recently I made the mistake to turn a TV on, and what I saw and heard, can certainly make you deaf, blind and stupid.
Parent
Re:sweet! (Score:4, Funny)
I'm going to dig up my old Hercules graphics card so I can drive one of those new green CRTs!
Parent
as a physicist and a canadian it is only right for (Score:5, Funny)
Re:as a physicist and a canadian it is only right (Score:5, Funny)
Parent
This means green jobs (Score:5, Funny)
Fantastic (Score:5, Funny)
All we need now is some true frickin' sharks and we're in business.
Snow Crash (Score:5, Interesting)
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)
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)
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.
Parent
Re:Snow Crash (Score:5, Interesting)
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.
Parent
Re: (Score:3, Informative)
RGB is the additive set of primary colours, CMY is subtractive.
Re: (Score:3, Informative)
depends on whether you're talking about primary additive colours [wikipedia.org] or primary substractive colours [wikipedia.org].
As the idea here is to send light in your eyes, and not buckets of paint, I guess additive is what you're looking for
What Headline/Summary Nonsense (Score:5, Interesting)
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
Re:What Headline/Summary Nonsense (Score:5, Informative)
Parent
Excellent story about excellent science. (Score:5, Informative)
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)
Parent
True green laser? (Score:5, Informative)
Not fake (Score:3, Interesting)
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....
My eyes! (Score:3, Funny)
The goggles do nothing!
Blackadder (Score:3, Funny)
Been nice knowing ya... (Score:3, Interesting)
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.
This is a pulsed laser, not continuous wave (Score:5, Informative)
Awesome. (Score:4, Interesting)
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
Re: (Score:3, Interesting)
If you were slowing down light to make it green you'd need to start with ultra-violet light, not infrared.
The real physics is well documented on Wikipedia. I recommend reading their page on non-linear optics. [wikipedia.org]
Re:Not doubling the infrared, but slowing by half. (Score:4, Informative)
Let me c [wikipedia.org].
Hang on a minute, the article says light travels at the same speed in a vacuum. Stupid intarwebs. I'll fix Wikipedia and you can do all the others, OK?
Parent
Re:Not doubling the infrared, but slowing by half. (Score:4, Insightful)
Nothing is slowed down. Light always goes at the same speed. Guess its name.
True in a vacuum, not true in practically anything else.
Parent
Re:Not doubling the infrared, but slowing by half. (Score:5, Informative)
That is not fully correct. It is true that the speed of light [wikipedia.org], in a vacuum, is a constant. But, the speed of light through a transparent medium is something less than c. How much light gets slowed down by a medium is frequency-dependent, as described by snell's law [wikipedia.org], which is how lenses are able to bend light.
The fact that the speed of light through a medium is less than c also allows for some more exotic phenomena, such as Cherenkov radiation [wikipedia.org], created when a particle's velocity through a medium exceeds that medium's speed of light (but definitely remains less than c).
Parent
Re:Lasers? Star Wars? (Score:5, Funny)
Hate to break it to you. They were props.
Parent
Re: (Score:3, Funny)
*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.
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.
Re: (Score:3, Informative)
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.