AmericanWeiner
09-28-2006, 10:52 AM
http://www.popsci.com/popsci/technology/b0b13ddbf6fed010vgnvcm1000004eecbccdrcrd.html
Highlights:
WHAT: A way to make objects invisible. The trick is to use metamaterial, a complex hybrid structure of metal and insulator that makes light move around an object like air flowing over an airplane wing. In a process called refraction, these materials interact with light in such a way that it travels faster through the metamaterial than it does through a vacuum, the famed c in Einstein’s special theory of relativity. Properly tuned, the light emerges from the shield as if there were no object present. But unfortunately for would-be spies, it’s very difficult to make cloaking devices that work on more than one wavelength of light at a time.
A bomber, tank or building covered in a radar-sensitive metamaterial shield would literally disappear from radar screens.
(As opposed to just appearing smaller as with currently deployed technology)
Duke University physicist David R. Smith hopes to shield a toaster-size object from microwave frequencies within the next six months. Metamaterials that work on visible light—which isn’t a single frequency but a spectrum of frequencies—are at a more primi- tive state. A specific meta- material design would be required to redirect each frequency in the visible range, and integrating that many components into a device might take 10 years for the initial lab demonstration alone.
Can the cloaking be perfect? Almost. Any metamaterial absorbs a little bit of light and therefore casts a slight shadow.
Yes, but current designs would work only if you painted yourself all one color. A cloak, which for comfort’s sake needs to be pretty thin, could bend radiation of just a single frequency, so it could only hide an object of one color. There’s a possibility, though, that a thick shell could include a wider variety of metamaterials and broaden the invisibility to multiple frequencies.
Highlights:
WHAT: A way to make objects invisible. The trick is to use metamaterial, a complex hybrid structure of metal and insulator that makes light move around an object like air flowing over an airplane wing. In a process called refraction, these materials interact with light in such a way that it travels faster through the metamaterial than it does through a vacuum, the famed c in Einstein’s special theory of relativity. Properly tuned, the light emerges from the shield as if there were no object present. But unfortunately for would-be spies, it’s very difficult to make cloaking devices that work on more than one wavelength of light at a time.
A bomber, tank or building covered in a radar-sensitive metamaterial shield would literally disappear from radar screens.
(As opposed to just appearing smaller as with currently deployed technology)
Duke University physicist David R. Smith hopes to shield a toaster-size object from microwave frequencies within the next six months. Metamaterials that work on visible light—which isn’t a single frequency but a spectrum of frequencies—are at a more primi- tive state. A specific meta- material design would be required to redirect each frequency in the visible range, and integrating that many components into a device might take 10 years for the initial lab demonstration alone.
Can the cloaking be perfect? Almost. Any metamaterial absorbs a little bit of light and therefore casts a slight shadow.
Yes, but current designs would work only if you painted yourself all one color. A cloak, which for comfort’s sake needs to be pretty thin, could bend radiation of just a single frequency, so it could only hide an object of one color. There’s a possibility, though, that a thick shell could include a wider variety of metamaterials and broaden the invisibility to multiple frequencies.