Slashdot Mirror
Laser Turns All Metals Black
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."
Surely if it absorbed all the light, it would be completely invisible, not black?
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...
It's official. Most of you are morons.
Since it's the holiday, the usual rants against the article submitter, Roland Piquepaille, have been rather muted. To sum up:
* 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.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
An older New Scientist article on a related technique reports 7 to 25 times less light reflected, compared to optical black paint. NS also reports on the current laser-based technology.
Escher was the first MC and Giger invented the HR department.
This "technology" is nothing new. Just a prof trying to make something mundane sound flashy.
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). 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.