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A Step Toward an Invisibility Cloak
Technology Review has a writeup on the latest advance in the lab towards an invisibility cloak made of metamaterials, described this week in Science. We've been following this technology since the beginning. The breakthrough is software that lets researchers design materials that are both low-loss and wideband. "The cloak that the researchers built works with wavelengths of light ranging from about 1 to 18 gigahertz — a swath as broad as the visible spectrum. No one has yet made a cloaking device that works in the visible spectrum, and those metamaterials that have been fabricated tend to work only with narrow bands of light. But a cloak that made an object invisible to light of only one color would not be of much use. Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, it's no longer effective. The cloak that Smith built is very low loss, successfully rerouting almost all the light that hits it."
Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, it's no longer effective.
Why would that be no longer effective? If the cloak reroutes 90% of the light, then you're left with 10% opacity, right? Sure, something that translucent would be very difficult to see, especially from a distance.
Direct link please!
http://www.technologyreview.com/computing/21971/?a=f
Garbage javascript broke for me and the page didn't get past a white page.
If visible light is being routed around the cloak, it could cause some serious navigation issues for the cloaked object. Maybe some objects (ships/aircraft) will only need a cloak that routes radar, leaving pilots to navigate by sight and dead reckoning (GPS uses radio frequencies, right?)
"works with wavelengths of light ranging from about 1 to 18 gigahertz"
frequency is in hertz.
wavelength is a length, so it will be in meters or feet or inches or volkswagen bugs.
that is all. </pedantic>
"The value of a man resides in what he gives,
and not in what he is capable of receiving."
--Albert Einstein
Pics or it didn't happen.
Metamaterials are interesting enough _whithout_ that stupid invisibility shit everytime.
I mean, lenses without diffration limit are also interesting. And opposed to the inisibility stuff, they might really work.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
Now I can see what happens inside the Girls' dorm!
Giggity-giggity-goo.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
1-18 ghz is way way broader than a very thin swat of visible light. Just looking at the spectra should show it. Mod me actually uninformative or overrater.
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Is it just me, or would this stuff work VERY well as a RADAR cloaking device?
1-18 GHz is solidly in the microwave (millimeter-wave RADAR anyone?) range...
- The race is not [always] to the swift, nor the battle to the strong. -
"Now [that] this is becoming a more feasible technology, we will start to see a lot more of it."
Heh, i thought the goal was to see a lot less of it :)
Patents Drive Free Software as Hurricanes Drive Construction Industry
I look forward to the photo of the prototype.
Actually, all claims require adequate support for provisional acceptance. Differing standards for differing claims derives from the concept of canon which has more of a place in religion than science.
I agree it would have been nice if they'd included a demonstration vid.
Loose lips lose spit.
Yep, that's the one. Frequencies should be thought of logarithmically. You can use the musical concept of octaves in this case. 1-18 GHz is about 4.17 octaves, whereas 400-750 THz is about 0.9 octaves.
ResidntGeek
You must be thinking of the 16k visual spectrum. This is referring to the Spectrum 128k.
Why would that be no longer effective? If the cloak reroutes 90% of the light, then you're left with 10% opacity, right? Sure, something that translucent would be very difficult to see, especially from a distance.
The Predator still got his ass shot up good with that hand-held vulcan gun, because the soldier saw the 10% of light that he couldn't cloak.
That's what you get for pissing off Jesse "the future Governor of Minnesota" Ventura.
Cloaking device or not.
You can't take the sky from me...
...and I ain't an engineer.
I bet you've a schoolteacher.
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...to light of only one color would not be of much use."
It would be exceptionally useful if that colour was infra-red.
I don't see why they're overdoing this so much. I've been able to become invisible for a long time--all I have to do is cover my eyes!
Try it today!
I fail to see what is so funny about that.
Mit der Dummheit kämpfen Götter selbst vergebens
Bah, "ain't" is a perfectly valid contraction for "am not", and has been since at least 1706. (See http://www.etymonline.com/index.php?search=ain't&searchmode=none) Proscriptionists object to it largely because it's often used for "is not", or "are not", which was seen as somehow "perverting" the English language.
In fact, though, "ain't" has been used that way since at least the 19th century.
About the worst that you can say of "ain't" is that it's inappropriate for a formal register, but so are most contractions.
Cheers,
Your Friendly Neighborhood Pedant
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7000 -> f = lambda/c -> 4.28275E+14
5000 -> f = lambda/c -> 5.99585E+14
Difference -> 1.713E+14 Hz -> 1.713E5 GHZ
About 171,000 GHZ not 17
If its in range, just do a sonar type at high freq, and you are bound to map something.
Liberty freedom are no1, not dicks in suits.