I was wondering... how do you control those lasers? To have a pulse of one femtosecond you would need something running at petahertz... of course I'm missing something...
Researchers Create Gold Aluminum, Black Platinum, Blue Silver
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Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#12I was wondering... how do you control those lasers? To have a pulse of one femtosecond you would need something running at petahertz... of course I'm missing something...
Abstract: Shaping of the phase, amplitude, and polarization state of an
ultrashort pulse is demonstrated using a novel arrangement of a single,
linear, high-resolution liquid crystal array. Orthogonal polarization components,
separated by a Wollaston prism, are manipulated independently and
re-combined in a near-common path, common-optic geometry.
http://www.opticsinfobase.org/DirectPDFAccess/D685BD2D-BDB9-...
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#132008? There's some interesting stuff from the same team summarized at this link: http://www.scienceblog.com/cms/person/chunlei-guo
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#14FTA: Since the process changes the intrinsic surface properties of the metal itself and is not just a coating, the color won't fade or peel, says Guo
Oversold. This is technically true, but any corrosion (or even scratching) will muck up the visible-wavelength-scale features on which this effect depends. I'd have to believe this kind of image would be far more fragile than a simple paint would be...
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#15This is dated February 1st, 2008. Shouldn't we be seeing applications of this by now?
Link above. Applications include micrometer-scale imaging using terahertz radiation, which is less dangerous than x-rays because it's non-ionizing, and several others...though past experience suggests that the time between lab discovery and commercial products is often a decade.
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#16What will happen to jewelry prices? Does this mean we can make perfect aluminum jewelry that looks like gold (except for weight and such)? Would people care if they could get real gold or fake aluminum that looks identical and is muuuuch cheaper?
Part of the magic of the Magic Shiny Rocks is that if it is not as expensive as real, genuine Magic Shiny Rocks it isn't as esteemed and makes you an evil, evil person. Except for using alloys or "flawed" Magic Shiny Rocks, those methods of generating Magic Shiny Rocks for cheapskates are traditional.
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#17FTA: Since the process changes the intrinsic surface properties of the metal itself and is not just a coating, the color won't fade or peel, says Guo Oversold. This is technically true, but any corrosion (or even scratching) will muck up the visible-wavelength-scale features on which this effect depends. I'd have to believe this kind of image would be far more fragile than a simple paint would be...
Perhaps a plastic coating to preserve the microstructures...
Still valuable, the colors apparently can be dialed up to order, unlike paint etc which depends upon mixing and batch etc.
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#18I was wondering... how do you control those lasers? To have a pulse of one femtosecond you would need something running at petahertz... of course I'm missing something...
Femtosecond lasers are actually common nowadays. We use a Ti-sapph at my lab.
Unless I'm crazy, Prat's answer is actually unrelated to your question. It's an article about pulse shaping, which is used to, well, change the shape of an ultra-short pulse. Not generate it.
What you want to look for is mode-locking. Essentially it's based on interference. You have a lot of standing waves in a laser cavity and lock them so that they all have the same phase. Then they'll interfere destructively except at a regular interval where they add up to make a powerful but very short pulse. Imagine water in a pool, if you generate waves just right you can get it to splash suddenly and powerfully in certain spots, even though your wave machine itself can't generate such strong splashes.
http://en.wikipedia.org/wiki/Mode-locking
Disclaimer: I use these lasers sometimes, but I'm in signal processing, not physics.
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#19Earlier quoted context omitted.
Just layer up a bunch of surfaces then :)
[deleted]
"its equivalent to top layer being transparent that lets light through one way but doesn't let it reflect back"
That would be a violation of the laws of thermodynamics. It's impossible to make a one way mirror. If you could, you could allow light through from one side, and collect free energy, since one side would be hotter than the other.
Re: Researchers Create Gold Aluminum, Black Platinum, Blue Silver
#20A line from star trek: "Transparent aluminum???"
Transparent aluminum is called alumina, and it exists, and it's incredibly hard. But not perfectly transparent (it's difficult to manufacture).