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Make Your Own Invisibility Cloak With a 3D Printer
cylonlover writes "Invisibility cloaks have been around in various forms since 2006, when the first cloak based on optical metamaterials was demonstrated. The design of cloaking devices has come a long way in the past seven years, as illustrated by a simple, yet highly effective, radar cloak developed by Duke University Professor Yaroslav Urzhumov, that can be made using a hobby-level 3D printer."
"ahhhhh, 3D printers, is there anything they can't do"
"certainly Homer, they can't make doughnuts"
!!!!
".....stupid 3D printers......."
You will see him hiding behind a big off-white disc with holes in it. Call me a nitpicker, but to me "invisible" is the opposite of "visible", which is the defining characteristic of what we call visible light. Being being undetectable to 10GHz frequencies, while impressive in its own light (haha), is most certainly not invisibility.
...but now I can't find my 3D printer
Radar is very 1 dimensional. A radio wave, imagined as a vector or ray, bounces off the material and then back at the receiving dish. If it doesn't, nothing is there as far as they can tell. However, if you broadcast on one side of the material and then received on the opposite side with a grid of multiple receivers, that might give away that something is there.
Though I think with this cloak, you wouldn't know specifically where it is. Radio waves warping around it would be received but not in the correct location unless you projected a grid of frequencies directly at it and then watched what geometric pattern they were received in then reversed it. You wouldn't know the object's exact location otherwise. Any cloak that simply makes the radar waves disappear though would show up easily. I believe this one does wrap the waves around though, instead of just absorbing them, just they wouldn't arrive quite correctly aligned on the other side the way they would if there was no object there so like I said, a grid would tell you the radar waves are being bent by something.
Read up on how they work ;-)
In short, no, they're not like blackholes.
The principle behind them is that emmissons heading into the cloak are routed around the object and then leave, and here's the clever bit, in a direction and intensity equal to what would happen if the invisible object wasn't there.
A drawback of this is, if you were building your cloak on the observable spectrum, if your inside the cloak you can't see anything outside of it (as all the incoming light gets diverted around you)! Admittedly it's only a draw back if looking around you is important, there's good reasons not to care and cool applications e.g. building a sea platform that is invisible to incoming waves (google it, my brain hurts from remembering so much already)
Well, it's invisible to that spectrum. And if you're invisible to radar, it is a limited form of 'invisible'.
Besides, inradarible sounds stupid. :-P
Lost at C:>. Found at C.
simple, yet highly effective, radar cloak
I know they used the word 'invisibility' which implies visual, but they do identify it as being invisible to radar.
Nothing to see here
“He’s not deformed, he’s just drunk!”
Given that the visibility you're talking about is less than 10% of the entire spectrum, I'd disagree and say that invisibility to any particular part of the spectrum, especially the parts used for detection of any kind is pretty damned impressive.
Python: 'And then suddenly you have a language which says "we're all stuck with whatever the whiniest coder wants".'
I think it can be integrated in flying cars, to have invisible 3D-printed flying cars.
As soon as I print a new cloak, I am coming after you! (Obama took my other one.)
If you see something; SAY something.
Before the terrorists and pedophiles use it to hide their crimes.
You can see him through the holes. It works for radar not for human eyes.
Why would you need to be invisible to radar to hang out in front of Starbucks?