From what I can tell, there's no new technology here, nothing depending on fundamentally new science; rather, it's just clever use of current technology. The system covers the object to be hidden with hexagonal tiles that can be set to specific temperatures, so that in the far IR, they can be set to look like either the background or a specific programmed shape. In that video, they make the tank look like a station wagon, for example. ("hey... what's a Volvo station wagon doing out here on the battlefield?")
To blend in with the background, each sensor panel can include a camera that observes the temperature of the environment on one side of the tank (over a small area), and the system then programs the pixels on the other side of the tank to those temperatures. The results is like looking through the solid object. Much like this clever guy did with his Halloween costume: using two iPad2 tablets on either side of his body. The combined cameras and videos allow you to see what's behind him, as if you're looking right through him.
Invisibility is a subject that gets a lot of university research. The technology to do this in visible light is very likely many years away, but imagine light-piping (fiber optics) an image from one side of a cloak to another, so that the objects on one side of you can be seen as if you weren't there. I expect the first uses will be to disguise soldiers from being seen from great distances; it will be a long time before you could stand near someone and not see them. Unless you're over 65.
Laboratory demonstrations have been around for a few years - mid2000s?. Shifting phase of micro/light waves. A few problems remain :) Think of the relative phase shifted across a surface related to the viewing angle of that surface. Toss in a few velocity vectors...
ReplyDeleteHowever, with the combination of development of THz+ electromagnetic transmitters (visible light being on the order of 500THz), I don't believe we're all that far from this becoming a practical reality at least in specialized applications.
I suspect mathematics similar to phase-nulling audio systems applied to a wavelength-sensitive dielectric interface.
We already have Dick Tracy's watch; now we have the cloak of invisibility. Didn't one of the Greek heroes use such a thing to kill Medusa?
Q
I've read about some things that do that sort of phase shifting, basically bending light around an object so that it appears to not be there. Readers: the key term to search is metamaterials.
ReplyDeleteThere's talk of an adaptation of a structure that can be built out of monopoles and placed around something to make it invisible to radar. http://www.physorg.com/news80488753.html
Real invisibility cloaks carry the somewhat serious problem that you can't see out from inside one; light flowing toward you will flow around you just as you want light flowing toward an observer to do. The metamaterial has to be anisotropic to let you see out. Any "window" gives the bad guys a way to see you.
So Star Trek was right. The Romulans always had to drop their cloak to use their long range sensors.
A post-doctoral researcher at the University of Pennsylvannia posts a series an electromagnetic simulation of EM waves going past a group of cloaked particles.
ReplyDeleteIf you were in the lower left of that plot, the waves would appear completely normal; you'd have no idea the cloaked objects were there.
Extending this to 3D and the full visible spectrum isn't trivial, but it's getting a lot of effort.