Finally, a True Green Laser

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."

Comments

Robustness, too!

[Sockatume]

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

Re:Robustness, too!

[kusanagi374]

A laser diode is much more robust than a laser diode

 

*head explodes*

Re:Robustness, too!

[Anonymous Coward]

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.

Re:Robustness, too!

[Mr. Underbridge]

*head explodes*

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

Re:Robustness, too!

[Allicorn]

(laser diode).robustness > ( (laser diode)+(frequency-doubling package of nonlinear crystals) ).robustness

Better?

Re:Robustness, too!

[Anonymous Coward]

expected ;

Re:Robustness, too!

[dmbasso]

it was Python, you insensitive clod!

Re:Robustness, too!

[noundi]

Do it yourself, it's open source.

Re:Robustness, too!

[CarpetShark]

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 ;

Re:Robustness, too!

[Eevee]

Would you settle for a member of the perciformes order with an attitude?

Re:Robustness, too!

[BubbaDave]

Geneva Accords, 32 Nations Summit, April 2039, Section 329, Paragraph 27.

Dave

Re:Robustness, too!

[wealthychef]

It's not illiteracy, it's attention deficit. Why read the whole sentence when you can just read until you've formed an opinion and ignore the rest?

Re:Robustness, too!

[wealthychef]

Then you left out a leading space.

Re:Robustness, too!

[gparent]

It's not illiteracy, it's attention deficit. Why read the whole sentence when you can just read

*head explodes*

Re:Robustness, too!

[Joe Snipe]

*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.

sweet!

[gEvil (beta)]

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!

Re:sweet!

[Jurily]

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.

Re:sweet!

[impaledsunset]

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.

Re:sweet!

[DrCode]

I'm going to dig up my old Hercules graphics card so I can drive one of those new green CRTs!

as a physicist and a canadian it is only right for

[ILongForDarkness]

me to be the first to say: "laaayyser".

This means green jobs

[Teresita]

I'm sure Al Gore is thrilled with this news of green laser technology.

Fantastic

[Rik Sweeney]

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

Snow Crash

[Derek Pomery]

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:Snow Crash

[Lumpy]

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

[Daniel Dvorkin]

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.

What Headline/Summary Nonsense

[Anonymous Coward]

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

[wigaloo]

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, 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.

True green laser?

[actionbastard]

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.

Re:Not doubling the infrared, but slowing by half.

[Dyslexicon]

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.

Re:Lasers? Star Wars?

[Anonymous Coward]

Hate to break it to you. They were props.

Blackadder

[kyriosdelis]

Oh, Edmund... can it be true? That I hold here, in my mortal hand, a nugget of purest Green?

Re:Not doubling the infrared, but slowing by half.

[Hognoxious]

Light always goes at the same speed. Guess its name.

Let me c.

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?

Re:Not doubling the infrared, but slowing by half.

[amorsen]

Nothing is slowed down. Light always goes at the same speed. Guess its name.

True in a vacuum, not true in practically anything else.

Been nice knowing ya...

[rayharris]

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.

Re:Not doubling the infrared, but slowing by half.

[necro81]

Nothing is slowed down. Light always goes at the same speed. Guess its name

That is not fully correct. It is true that the speed of light, 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, 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, created when a particle's velocity through a medium exceeds that medium's speed of light (but definitely remains less than c).

This is a pulsed laser, not continuous wave

[rcb1974]

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.

Re:as a physicist and a canadian it is only right

[autocracy]

They say the same thing, but they say it after the Canadian physicist.

Excellent story about excellent science.

[Futurepower(R)]

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 of the Applied Physics Express scientific paper. (Free)

Re:White laser lights?

[lorenlal]

Now the trick is finding enough sharks to make the display useful.

Modern Major General

[BancBoy]

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.

Was I wrong to read that as if it was written by Gilbert & Sullivan?

Awesome.

[Facegarden]

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

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