Last week we had the laser gunship, this week it's the invisibility cloak.
Sounds a lot like science fiction but you'd be surprised how close Army researchers are to actually attaining the Holy Grail of invisibility.
According to Dr. Richard Hammond, a theoretical physicist with the Optical Physics and Imaging Science department of the Army Research Office, engineers are closer than they've ever been to developing a material that can bend light around an object rendering it invisible to certain wavelengths -- light being one of them.
So far scientists have successfully tested so-called "meta-materials" -- ones that are man made and built at the molecular level -- that can render an object invisible to microwaves, which has a larger wavelength than light, Hammond said.
"This is a new paradigm for the science of light," he said during a DoD bloggers' roundtable today. "It can be bent [using these materials] in an almost arbitrary way."
There are some significant obstacles to making a usable "invisibility cloak," however. The main one is the material itself. Since it has to be build at the molecular level, making enough material to cover, say, a truck is still out of reach, Hammond said. Also, so far the science is there to block one kind of wavelength, but not another. So you could render an object invisible on the UV spectrum but not the visible light one at the same time. And if you made something invisible to the human eye, it would be impossible without some kind of other sensor for whoever's behind the object to see anything since you're robbing him of light.
"But in early applications we could shield an object from radar," Hammond added.
Closer to fielding is a similar technology using meta-materials that can enhance optics to see things at the cellular or even molecular level -- "smaller than the wavelength of light," Hammond said, or less than .5 microns.
These "Super Lenses" could be used to detect chemical or biological agents, focus visible light to a single point to "uncloak" cloaked objects or help recharge solar-celled batteries, and could be applied to microscope lenses to increase magnification ten times, Hammond said.
Hammond has been working with UC Berkley, University of Colorado at Boulder, Perdue and Princeton on these efforts under a three-year, $1 million grant.
-- Christian
