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Researchers Create Gold Aluminum, Black Platinum, Blue Silver
- jxcole 17y agoA line from star trek: "Transparent aluminum???"
- prat 17y agoIf it wasn't just a surface effect, that could have been possible:)
- sp332 17y agoJust layer up a bunch of surfaces then :)
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- ars 17y ago"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.
- eru 17y agoOf course you can make imperfect or active one-way mirrors.
- ars 17y agoNot sure what an imperfect one-way mirror is. Do you mean, something that is mostly one way? Because, no, you can't. And you can't make an active one-way mirror either (at least not without inputting energy) - see http://en.wikipedia.org/wiki/Maxwells_demon http://en.wikipedia.org/wiki/Maxwells_demon
- DLWormwood 17y agoYou've never seen a security mirror (http://www.howstuffworks.com/question421.htm http://www.howstuffworks.com/question421.htm) before? They're what the parent posters are refering to...
- ars 17y agoI was waiting for someone to mention those. They are not one way. Not in the slightest. You can turn them around, and they will work unchanged. They transmit exactly the same amount in both directions. The only reason they seem to work is that one room is well lit, and the other is dark. So it's hard to see anything from the well lit room. They are half silvered, so they reflect half, and transmit half. The well lit room then reflects lots of light, but is receiving little light from the dark room. The dark room reflects little light, but is getting lots from the well lit room.
- DLWormwood 17y ago> They are not one way. Not in the slightest. Hence the references to "imperfect" a few messages back. Pedantry of the kind you're exposing is dangerous (even life threatening) in real life.
- ars 17y agoBut it's not "imperfect". It's 0. It's not one way in the slightest. If I turn the lights off in my house and you can't see me through an open window will you tell me the open window is a one way window? Imperfect implies say, 49% of light goes one way and 51% goes the other. Such a mirror does not exist. And please remember the context (although I think the poster was embarrassed and deleted his original comment), we are talking about making black colors on metal, and he was wondering if it's because it's a one way mirror.
- ars 17y agoTransparent aluminum is called alumina, and it exists, and it's incredibly hard. But not perfectly transparent (it's difficult to manufacture).
- jacquesm 17y agoAll metals are transparent if the layer is thin enough.
- GrandMasterBirt 17y agoWhat 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?
- prat 17y agoI guess that already happens.. they have fakes for everything from gold to diamonds. Electroplating was invented long back - however, the fact that this technique prevents peeling off etc., means that fakes would be more durable. In any case, I think there is probably something more cutting edge they can do with this technology.
- patio11 17y agoPart 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.
- djcapelis 17y ago> Would people care if they could get real gold or fake aluminum that looks identical and is muuuuch cheaper? Yes. Neither diamonds or gold are really that desirable for jewelry. Gold is a metal that doesn't hold its shape very easily and good diamonds come in one color: colorless. The desirable part comes from the fact that they're rare. Rare things are fashionable. There's been ways to produce artificial diamonds for some time now. Some of them actually have some really awesome properties when it comes to ultraviolet light. They actually glow and it's downright beautiful. A "genuine" diamond doesn't, since the ones actually created in the earth have to work out impurities the hard way and aren't as pure as at least one of the artificial processes. Yet the popularity of natural diamonds continues. Frankly some of the other precious gemstones look nicer for many pieces, it's the rarity and implication of wealth that causes people to care about diamonds.
- mwexler 17y agoI'm just waiting for the Red Kryptonite.
- sker 17y agoThis is dated February 1st, 2008. Shouldn't we be seeing applications of this by now?
- anigbrowl 17y agoLink 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.
- dstein64 17y agoHere is a December 8, 2009 article from the University of Rochester website that describes some additional uses: http://www.rochester.edu/news/show.php?id=3514 http://www.rochester.edu/news/show.php?id=3514
- capablanca 17y agoI 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...
- prat 17y agoAbstract: 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-BDB9-137E-C384F715FF304597_148541.pdf?da=1&id=148541&seq=0 http://www.opticsinfobase.org/DirectPDFAccess/D685BD2D-BDB9-...
- ramchip 17y agoFemtosecond 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 http://en.wikipedia.org/wiki/Mode-locking Disclaimer: I use these lasers sometimes, but I'm in signal processing, not physics.
- prat 17y agoThanks.. that explains the generation of the pulse - the link I posted probably relates to fine tuning the shape to get the desired color.
- anigbrowl 17y ago2008? There's some interesting stuff from the same team summarized at this link: http://www.scienceblog.com/cms/person/chunlei-guo http://www.scienceblog.com/cms/person/chunlei-guo
- ajross 17y agoFTA: 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...
- JoeAltmaier 17y agoPerhaps 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.
- ajross 17y agoA polymer coating would indeed help. In the jargon, we call that stuff "paint". :)
- jacquesm 17y agoI think the GP meant a varnish, not a paint.
- ajross 17y agoThere's absolutely no difference; those are both completely informal terms. A "varnish" (or whatever, there are thousands of names for these thing) is nothing more than a transparent paint base without pigment added. The point was that the claim was made in the article that this is more durable than paint, when AFAICT the only way to make it so it to put a paint(-like coating) on top of the surface anyway. So how is it more durable? Scratch the coating and you scratch off the fancy micro-texture.
- jacquesm 17y agoIt could for instance be more durable because it doesn't fade due to ultra-violet light breaking down the pigment.
- wheaties 17y agoHaving personally worked with Guo while he was setting up his lab, I'm really pleased to see him linked on this website. The man is damned smart and it's very true what he said. For those wonder how it all works check out: http://www.optics.rochester.edu/workgroups/guo/team/guo.htm http://www.optics.rochester.edu/workgroups/guo/team/guo.htm and some of his papers.
- twism 17y agoNice, I can't wait for rappers to start donning and rapping about their new multicolored gold chains.
- rcfox 17y agoI'm surprised no one has mentioned this yet, but this is the secret to alchemy! A couple of laser bursts and you can turn lead to gold. Just watch out for anyone named Saro...
- tdziuba 17y agoWe have been doing that for years but we called it "paint".