Finally, a True Green Laser 274
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."
Robustness, too! (Score:5, Interesting)
A laser diode is much more robust than a laser diode and the frequency-doubling package of nonlinear crystals.
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."
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
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....
Re:Not doubling the infrared, but slowing by half. (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]
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.
Re:Why not InGaN? (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.
It's not illiteracy (Score:3, Interesting)
It's a bug in the language.
Re:It's not illiteracy (Score:2, Interesting)
'free of ambiguity' is not something I see as a goal for a spoken language, so I might call it an implementation detail, but I wouldn't call it a bug.
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.
Re:White laser lights? (Score:2, Interesting)
We already have RGB + White lasers (consisting of multiple diodes), but I haven't seen anything useful done with them.
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