Laser Turns All Metals Black 333
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."
anything special? (Score:4, Insightful)
Re:anything special? (Score:4, Informative)
Re:anything special? (Score:5, Funny)
Re:anything special? (Score:5, Funny)
I also noticed that the summary was written (Score:3, Funny)
A laser that turns all metals black. All metals being copper, zinc, and gold. As if these are the only metals around.
Time to wake up. It isn't the bronze age anymore.
Re:anything special? (Score:5, Funny)
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1 W during 1 second is about 1e15 watts during 1 femtosecond. That's a bunch of watts. A BUNCH. You can't provide that kind of power for a long period with a wall outlet. In order to provide the amount of power the North American grid consumes at all times you need - er - the North American grid.
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.
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Guo's research team has tested the absorption capabilities for the black metal and confirmed that it can absorb virtually all the light that fall on it, making it pitch black.
Surely if it absorbed all the light, it would be completely invisible, not black?
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...
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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.
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.
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I don't know about that; though Roland mentions it in his typically breathless puff, TFA doesn't. I can understand these nanostructures absorbing light, with wavelengths similar to their scale, but not microwaves, radar, etc. with wavelenghths of centimetres. But absorbing all light is going to make things heat up. It will be emitting more infrared
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Special Properties (Score:5, Funny)
Well, that one property alone makes it excellent for building Ford Model-Ts.
Re:anything special? (Score:5, Interesting)
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Mr. H. Desoto (Score:3, Funny)
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Episode 6: Hitchhikers Guide to the Galaxy [sadgeezer.com]
"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.)
Comment removed (Score:5, Interesting)
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I know - boring
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Re:How black is it? (Score:5, Funny)
Re:How black is it? (Score:5, Informative)
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Re:How black is it? (Score:5, Funny)
Re:How black is it? (Score:4, Funny)
Cheers,
J.
Re:How black is it? (Score:4, Funny)
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Applications (Score:2, Informative)
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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.
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Or maybe I'm just an idiot. That's always an option.
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> an hour wouldn't you think something odd was going on?
Yes, but by the time you see it it's too late. The range at which your radar can detect an object is proportional to the size of its signature.
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So I guess you have to choose... you can be really hard to find but easy to laser a hole into, or really easy to find but really hard to laser a hole into.
One of the things I (
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> 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.
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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
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Good idea. Paint or adhesive preparation is a possible application.
Laser etching craze (Score:2, Interesting)
Dethklok (Score:2)
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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]
Obligatory Spinal Tap ref (Score:2, Funny)
"wall outlet" ease of the use (Score:4, Funny)
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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.
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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>
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)
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I skimmed through the full PDF and noticed that this is only a surface effect.
So... while this may be better than every other alternative so far, how is it different than the various chemical/heat based processes that create bonds between [material] & [surface coating]? Either
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Of course I didn't RTFA, because that's cheating, but anodising and various paints can produce a reasonable result (say 70-80% effective) for pennies per sq foot. Since collected heat is proportional area * efficiency, you could get the same result by using 20-50% more area.
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Before people refute this with silly assumptions remember that the sun does not put out white light of uniform intensity over the entire spectrum.
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The black panels absorb and retransmits the light, but since their temperature is far lower than the sun the retransmitted light is lower wavelength (ie infra-red). The glass used (or all glass?) is opaque to infra-red, so the infra-red heat energy is re-absorbed and doesnt escape.
A double glass layer on top is even better for stopping the heat loss since it insulates the inner glass panel from convective currents.
So... (Score:2)
Hey, Roland the Plogger has to work Thanksgiving (Score:2)
He's BAACK! Roland the Plogger, at it again, flogging his blog.
Make everything metal (Score:2, Funny)
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.
So maybe.... (Score:2, Interesting)
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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.
Also, Roland (Score:2)
You are a genius.
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.
*Any* Metal? (Score:2)
So if I take one of these lasers and swap out the one in my CD player, will all my White Snake albums come out as Black Sabbath?
You realise what this means, right? (Score:5, Funny)
What colour black? (Score:2)
Wait, i don't live in north america and have a line into THE NATIONAL GRID, guess i can't power one
Congradulations on a milestone (Score:3, Funny)
In related news... (Score:2)
Can it be used for long term archival (Score:3, Interesting)
Re:Can it be used for long term archival (Score:4, Informative)
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.
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You don't think maybe they would have tried that before reporting the results?
Paint lacks an important property (Score:2)
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Re:Blackness (Score:5, Interesting)
Solar (Score:4, Insightful)
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Having an aircraft made out of treated metal would make it one heck of a (visually) stealth plane. As it is, the U.S. stealth planes require a going-over with a fine tooth comb after each mission to ensure no scratches, dents, or chips are in the paint. Presumably a metal approach would reduce turn around time.
Oh yea, and black kicks
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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.
Re:Blackness (Score:5, Funny)
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If it did, I'd love to have some of my blades treated with it because keeping the good carbon steel ones well oiled can be a pain at times. Also, since it apparently uses small amounts of power to acheive, I can see this used in a lot of industrial applications.
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> gird? Otherwise I think I might have noticed the entire grid failing all at
> once, especially since one would assume they've performed the experiment
> multiple times....
You might want to take note of the fact that the length of said burst is a femtosecond.
> Plus I'd hate to see that poor bastards electrical bill....
The average power level is quite modest.