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Laser Turns All Metals Black
Posted by
Zonk
on Thu Nov 23, 2006 08:40 PM
from the bzoooom-whaaaawwwww dept.
from the bzoooom-whaaaawwwww dept.
Roland Piquepaille writes "Researchers at the University of Rochester have found a way to change the properties of almost any metal by using a femtosecond laser pulse. This ultra-intense laser blast creates true 'black metal' from copper, gold or zinc by forming nanostructures at the surface of the metal. As these nanostructures capture radiation, the metals turn black. And as the process needs surprisingly low power, it could soon be used for a variety of applications, such as stealth planes, black jewels or car paintings. But read more for additional references and a picture of this femtosecond laser system."
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UltravioletLED writes "A company in Petaluma, California has developed highly programmable desktop lasers. The same devices used in hospitals could also be used to turn any metal surface black by simply changing the software. From the article: 'The technology once filled a large room at DARPA until Raydiance scientists made it into a compact, tabletop unit. Schuler (The CEO) said he hopes it will replace just about any cutting device you can think of, from a big metal saw to a precise surgical blade ... Now that it's a little bigger than a breadbox, researchers want to use them to kill tumors, identify friend or foe during combat, and even remove tattoos.' Femtosecond lasers for eye surgery have been around for years now, but these new lasers are far smaller and promise to have much greater versatility."
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Hardware: Laser Blast Makes Regular Light Bulbs Super-Efficient 559 comments
guruevi writes with news that a process using an ultra-powerful laser can crank up the efficiency of everyday incandescent light bulbs. Using the same laser process covered several years ago, the tungsten filament has an array of nano- and micro-scale structures formed on the surface making the resulting light as bright as a 100-watt bulb while consuming less electricity than a 60-watt bulb and remaining much cheaper to produce. "The key to creating the super-filament is an ultra-brief, ultra-intense beam of light called a femtosecond laser pulse. The laser burst lasts only a few quadrillionths of a second. To get a grasp of that kind of speed, consider that a femtosecond is to a second what a second is to about 32 million years. During its brief burst, Guo's laser unleashes as much power as the entire grid of North America onto a spot the size of a needle point. That intense blast forces the surface of the metal to form nanostructures and microstructures that dramatically alter how efficiently light can radiate from the filament."
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anything special? (Score:4, Insightful)
Re:anything special? (Score:4, Informative)
Parent
Re:anything special? (Score:5, Funny)
Parent
Re:anything special? (Score:5, Funny)
Parent
Re:anything special? (Score:5, Funny)
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Re:anything special? (Score:4, Informative)
The technical meaning of the word "power" is energy consumed or produced per unit time. So a fairly small amount of energy can result in a huge amount of power if it's produced or consumed quickly.
Parent
Re:anything special? (Score:5, Funny)
Hint: Think "perfect stealth", not only for planes, but for your car as well. Make that cop toting the radar gun go insane.
Parent
Re: (Score:3, Informative)
Special Properties (Score:5, Funny)
Well, that one property alone makes it excellent for building Ford Model-Ts.
Parent
Re:anything special? (Score:5, Interesting)
Parent
Re:anything special? (Score:5, Informative)
No, because if it was invisible you'd be able to see what was behind it; if it merely absorbs the light that falls on it, you'd see a black shape instead...
Parent
Re:anything special? (Score:4, Insightful)
Now I see why the military might be interest in this. It isn't just an alternative to paint.
Parent
Mr. H. Desoto (Score:3, Funny)
"true 'black metal'"?! (Score:4, Funny)
This ultra-intense laser blast creates true 'black metal'
Rubbish, true [youtube.com] 'black [youtube.com] metal' [youtube.com]
(sniff... brings back memories of seeing them in '83.)
How black is it? (Score:5, Interesting)
-jcr
Re: (Score:3, Funny)
I know - boring
Re:How black is it? (Score:5, Funny)
Parent
Re:How black is it? (Score:5, Informative)
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Re:How black is it? (Score:5, Funny)
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Re:How black is it? (Score:4, Funny)
Cheers,
J.
Parent
Re:How black is it? (Score:4, Funny)
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Picture (Score:5, Funny)
I really should just go to bed...
DugUK
Hey look the Roland Template Script is back (Score:3, Interesting)
and his additional references [google.com]
"wall outlet" ease of the use (Score:4, Funny)
black (Score:5, Funny)
Obligatory Pigpile Rant (Score:4, Informative)
* He gets a lot of articles posted to the front page, which makes the rest of us jealous.
* His articles tend toward pseudoscience, or at least towards the sort of flashy, headline-inspiring science that does little to advance human knowledge.
* He used to link to his personal blog, which really irritated people who'd love to have their own blogs get Slashdotted on a regular basis.
* He now links to his zdnet blog, which really irritates people who'd love to have their own blogs get picked up by a big corporate website.
* To top it all off, he's French, so all the right-wing nutters hate him automatically.
My irritation comes mostly from the second point -- and, I'll confess, the first as well. But as his defenders (and even the Slashdot editors) have noted, it's not like he's got some inside line to CmdrTaco's desk. He just finds himself at the right place at the right time.
Nonetheless, I recommend continuing to tag his articles with "pigpile", just so's we can keep up.
Re:Obligatory Pigpile Rant (Score:4, Informative)
He adds a link to his blog using "additional references and a picture" (or variants) as the text. This results in him getting higher google rankings for his blog, particularly for "additional references and a picture" (or variants). Note the Related Links at the top right of the Slashdot page for this article. In addition to a standard "slashvertisement", the effects also amount to a "googletisement".
While in ordinary circumstances this could potentially be acceptable, the contents of Roland's blog entries are usually redundant (including the picture) to the very articles he is reviewing in his blog. This amounts to an abuse of the trust provided by the Slashdot community.
Many people warn other slashdotters by adding the tag "pigpile" (for those who have tagging enabled). However, more people use the Greasemonkey script [userscripts.org] that will block Roland's pseudoscientific submissions, which brendandonhue [slashdot.org] posted in a previous Pigpile thread [slashdot.org]. That is why the Pigpile rants are low, not necessarily the holidays.
- RG>
Parent
Meh (Score:5, Funny)
Space-age technology! (Score:5, Funny)
*bows to Mr Adams*
black... (Score:5, Funny)
(and silver, and bronze..)
Solar collectors (Score:4, Interesting)
That's not all (Score:5, Funny)
All metals huh? (Score:3, Insightful)
Since when were there only 3 metals known to mankind? The summary blows.
Then you look at the articles.
"The key to creating black metal is an ultra-brief, ultra-intense beam of light called a femtosecond laser pulse. The laser burst lasts only a few quadrillionths of a second. To get a grasp of that kind of speed--a femtosecond is to a second what a second is to about 32 million years."
And:
"Currently, the process is slow. To alter a strip of metal the size of your little finger easily takes 30 minutes or more, but Guo is looking at how different burst lengths, different wavelengths, and different intensities affect metal's properties. Fortunately, despite the incredible intensity involved, the femtosecond laser can be powered by a simple wall outlet, meaning that when the process is refined, implementing it should be relatively simple."
I'm guessing this has to do with etching an intricate structure. Perhaps also that the laser can only be fired at a given rate. None of this is explained at all well.
This is a big deal for fuel cells. (Score:5, Insightful)
This technology has huge ramifications for chemical reactions that need a catalyst, and also in the area of fuel cells.
Unlike Roland, I actually try to link to the article and not some empty blog. Roland, your technology trends suck. Link to the originating article you fool!
Physorg [physorg.com]
Also, does Roland even have a degree in science? Because he sure doesn't ever seem to have a grasp of the important things in the articles he submits.
May not be such a great idea for consumer items (Score:3, Interesting)
It certainly does have some applications, and optics seems to be the obvious place. Having an emissivity of (well, they didn't say) 1e-8 would certainly make baffles more efficient.
You realise what this means, right? (Score:5, Funny)
Congradulations on a milestone (Score:3, Funny)
Can it be used for long term archival (Score:3, Interesting)
Re:Can it be used for long term archival (Score:4, Informative)
Parent
Hardly for car paintings (Score:3, Informative)
"For example, blackening a piece of metal the size of a little finger currently takes about 30 minutes."
And matt black hasn't ever been a favourite car color.
Nothing to see, move along. (Score:5, Informative)
Hit things with enough laser fluence and the surface atoms will move around, and may even be blasted off of the surface. This is the basis of a standard materials synthesis technique, pulsed laser deposition (PLD) [wikipedia.org]. Hit a target with a laser, and collect the ejected material on a nearby crystal.
Anyone who has done PLD knows that the surface of the target gets rough when you blast it. If the target is a metal, and the roughness is smaller than the wavelength of light (nanoscale), it will absorb light - it will be black.
In any case, the article asserts that the "blackness" is a material property and is therefore permanent. Nonsense. Touch it and the surface particles will rub off, leaving behind a shiny metal surface. Further, I'd be extremely surprised if there weren't tons of existing patents on surface modification by lasers. There are certainly tons of academic publications on the topic.
Re: (Score:3, Informative)
Maybe. The thing about reflecting photons is that the same material can be opaque, transparent, or reflective depending on the wavelength of the photons in question. It sounds like this technique makes a very good black for optical frequencies. Whether it's also black to radio waves needs to be investigated.
-jcr
Re: (Score:3, Informative)
No it doesn't. It is obvious that it is not. The process makes the metal black by creating an intricate surface structure on the scale of the wavelengths of visible light. It would look like a shiny metal surface at the centimeter or so wavelengths used by radar. The effect probably peters out somewhere in the infrared.
Re: (Score:3, Interesting)
Who says it's impossible to rub off? It's a very thin surface treatment. A quick rub with sandpaper should remove it to ordinary metal. And no reason you coudn't paint over it. Actually paint might adhere better to a fuzzy surface like this, when repaintin
Re: (Score:3, Informative)
> lasers to take out missiles while they were in the air, someone suggested
> that they make them as shiny (in all spectrums) as possible to reflect rather
> than absorb the military laser.
Doesn't work. The electric field intensity at the surface of the target is so high it exceeds the work function of the material and rips electrons right off the atoms. This creates a plasma layer that efficiently absorbs the radiation.
Re:Blackness (Score:5, Interesting)
Parent
Solar (Score:4, Insightful)
Parent
Re: (Score:3, Interesting)
Re:Blackness (Score:5, Interesting)
For those having difficulty reconciling the "entire power output of the US from a standard AC outlet" thing, understand that you are radiating for a ridiculously short period of time, so you can get a very high peak power in that pulse while still having a very low average power usage if you can unload a decent percentage of the entire duty cycle's worth of power in that one pulse. The Nd:YAG machines that I worked with were only 90 watts or so CW (continuous wave), but when you cranked the Q-switch down to a low enough rate, you could get a peak power in excess of a quarter-million watts in each 10 microsecond pulse. 10 microseconds is 10 *billion* times longer than a femtosecond (same comparison: one second to 317 years), so you have the possibility of having staggeringly large peak powers in these really short pulses.
Parent
Re:Blackness (Score:5, Funny)
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