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The First White Laser
IEEE Spectrum ^ | 27 Jul 2015 | Charles Q. Choi

Posted on 07/29/2015 3:54:30 PM PDT by Talisker

Scientists and engineers at Arizona State University, in Tempe, have created the first lasers that can shine light over the full spectrum of visible colors. The device’s inventors suggest the laser could find use in video displays, solid-state lighting, and a laser-based version of Wi-Fi.

Although previous research has created red, blue, green and other lasers, each of these lasers usually only emitted one color of light. Creating a monolithic structure capable of emitting red, green, and blue all at once has proven difficult because it requires combining very different semiconductors. Growing such mismatched crystals right next to each other often results in fatal defects throughout each of these materials.

But now scientists say they’ve overcome that problem. The heart of the new device is a sheet only nanometers thick made of a semiconducting alloy of zinc, cadmium, sulfur, and selenium. The sheet is divided into different segments. When excited with a pulse of light, the segments rich in cadmium and selenium gave off red light; those rich in cadmium and sulfur emitted green light; and those rich in zinc and sulfur glowed blue.

The researchers grew this alloy in stages, carefully varying the temperature and other growth conditions over time. By controlling the interplay between the vapor, liquid, and solid phases of the different materials that made up this nano-sheet, they ensured that these different crystals could coexist.

The scientists can individually target each segment of the nano-sheet with a light pulse. Varying the power of the light pulses that each section received tuned how intensely they shone, allowing the laser to produce 70 percent more perceptible colors than the most commonly used light sources.

Lasers could be far more energy-efficient than LEDs: While LED-based lighting produces up to about 150 lumens per watt of electricity, lasers could produce more than 400 lumens per watt, says Cun-Zheng Ning, a physicist and electrical engineer at Arizona State University at Tempe who worked on the laser. In addition, he says that white lasers could also lead to video displays with more vivid colors and higher contrast than conventional displays.

Another important potential application could be "Li-Fi", the use of light to connect devices to the Internet. Li-Fi could be 10 times faster than today’s Wi-Fi, but "the Li-Fi currently under development is based on LEDs," Ning says. He suggests white-laser based Li-Fi could be 10 to 100 times faster than LED-based Li-Fi, because the lasers can encode data much faster than white LEDs.

In the future, the scientists plan to explore whether they can excite these lasers with electricity instead of with light pulses. They detailed their findings online 27 July in the journal Nature Nanotechnology


TOPICS: Technical
KEYWORDS: laserprivilege; lasersberayciss; racistlasers; stringtheory
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1 posted on 07/29/2015 3:54:30 PM PDT by Talisker
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To: Talisker

*cough* racist *cough*


2 posted on 07/29/2015 3:55:21 PM PDT by GeronL
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To: GeronL

LOL! You beat me to it!


3 posted on 07/29/2015 3:56:14 PM PDT by MeganC (The Republic of The United States of America: 7/4/1776 to 6/26/2015 R.I.P.)
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To: Talisker

BFL


4 posted on 07/29/2015 3:57:04 PM PDT by Lurkina.n.Learnin (It's a shame nobama truly doesn't care about any of this. Our country, our future, he doesn't care)
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To: MeganC

It was way too obvious!

That light is just racist. heh


5 posted on 07/29/2015 3:57:50 PM PDT by GeronL
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To: Las Vegas Dave; ShadowAce; 6SJ7; AdmSmith; AFPhys; Arkinsaw; allmost; aristotleman; autumnraine; ...
Looks like lucrative US patents on the way, along with better, cheaper TVs, and cool death rays! Thanks Talisker.

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6 posted on 07/29/2015 4:00:24 PM PDT by SunkenCiv (What do we want? REGIME CHANGE! When do we want it? NOW)
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To: Lurkina.n.Learnin
BFL

Fascinating abbreviation, I just looked it up.

Almost like it was made for me, LOL...

7 posted on 07/29/2015 4:01:49 PM PDT by Talisker (One who commands, must obey.)
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To: Talisker

If he’s a new Marvel Superhero, he’s got to be gay.


8 posted on 07/29/2015 4:04:19 PM PDT by PGR88
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To: Talisker

Ok, I have a stupid question for our resident science gurus.

Why haven’t we developed a hand-held Laser weapon?

We have Lasers that easily cut through steel. Is it because of strength dilution at distance, or because there’s no way to stop at one kill, in other words, Laser goes through 6 people instead of one?
Or is it an energy generation issue, still requires more power generation than we can carry?


9 posted on 07/29/2015 4:12:57 PM PDT by rikkir (You can lead a horde to knowledge but you canÂ’t make them think. (TnkU Ctdonath))
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To: rikkir

Energy. Lasers are hooked to the power grid. My guess is that battery lasers would not cut thru steel. Or it could cut thru steel for about 2 seconds then need a recharge.


10 posted on 07/29/2015 4:15:24 PM PDT by central_va (I won't be reconstructed and I do not give a damn.)
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To: rikkir

the problem with the a hand held laser weapon is primarily the thick cord that makes it unwieldy and hard to aim


11 posted on 07/29/2015 4:16:10 PM PDT by bert ((K.E.; N.P.; GOPc.;+12, 73, ..... No peace? then no peace!)
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To: GeronL

The perfect weapon to blind enemy troops or pilots.


12 posted on 07/29/2015 4:17:24 PM PDT by MHGinTN (Is it really all relative, Mister Einstein?)
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To: Talisker

LOL. The first time I saw it I thought it stood for “ big Fn loser” . I thought that was rather rude. Bump for Later


13 posted on 07/29/2015 4:17:27 PM PDT by Lurkina.n.Learnin (It's a shame nobama truly doesn't care about any of this. Our country, our future, he doesn't care)
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To: bert

And that the thick cord is attached to the better part of your local power grid.


14 posted on 07/29/2015 4:18:29 PM PDT by USNBandit (Sarcasm engaged at all times)
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To: Talisker

#WhiteLasersMatter


15 posted on 07/29/2015 4:20:20 PM PDT by Rastus
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To: rikkir

Once upon a time when I was a student working in a lab with a fairly powerful laser, I had to do all manner of safety stuff and learned a good bit about the equipment.

One of the more notable things was that it was a single digit watt output laser, which had a kilowatt power source which plugged into the wall.

No doubt there are more efficient set ups than I used oh so many years ago, but the simple truth is that lasers are just not very efficient in terms of energy in vs. energy out. The ones used on the ABL for example are chemical lasers, so they work by causing a chemical reaction which dumps a lot of energy in a short time, which creates the beam.


16 posted on 07/29/2015 4:22:49 PM PDT by drbuzzard (All animals are created equal, but some are more equal than others.)
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To: MHGinTN

Shh!
Don’t tell Obama.


17 posted on 07/29/2015 4:24:40 PM PDT by RandallFlagg (With the things that are about to come to light. People might just need a little old-fashioned.)
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To: PGR88

I was thinking the generation basketball coach/physicist based on the white shadow tv series.


18 posted on 07/29/2015 4:24:49 PM PDT by wally_bert (There are no winners in a game of losers. I'm Tommy Joyce, welcome to the Oriental Lounge.)
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To: central_va

So as we come across Higher output, quicker charge batteries such as the one being developed by Musk, or the Graphene Battery, we might see an answer to the energy issue.

Would the “steel cutting” Laser maintain its lethality at 50-60 yards, or 100 yards?


19 posted on 07/29/2015 4:26:15 PM PDT by rikkir (You can lead a horde to knowledge but you canÂ’t make them think. (TnkU Ctdonath))
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To: rikkir

Theoretically a laser has infinite range, the question is focus.


20 posted on 07/29/2015 4:28:33 PM PDT by central_va (I won't be reconstructed and I do not give a damn.)
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