Scientists working on methods to make objects "Invisible" :
Some scientists seem to take their cues from science fiction or fantasy novels.
Physicists in Texas have
developed a method to make objects "invisible" within a limited range of
light waves. It's not Harry Potter's invisibility cloak just yet, but
scientists say it has a lot of potential.
The desire to become
invisible dates back to the ancient Greeks, if not further. In
mythological literature, gods and goddesses donned a headdress to
disappear from sight. Like Potter's cloak, the "cap of invisibility" was
imbued with magical powers.
A fixture in magic, the invisibility cloak has now advanced to science.
New technology makes troops invisible
Researchers at the University of Texas in Austin have developed a thin material called a 'mantle cloak,' according to a report published in the New Journal of Physics Tuesday.
If an object is wrapped
in it, it 'disappears,' but the effect only applies to a limited range
of light waves -- specifically microwaves.
The future is not here just yet
In their experiment, the
physicists covered a cylinder about a foot long and an inch or so in
diameter with the material. Microwave detectors could no longer plainly
'see' it, although it was still visible to the human eye. But the same
principle could be transferred to the range of perceptible light,
researchers say.
Doing so would then make objects invisible to the human eye.
The effect only covers a
very small band of electromagnetic waves at one time, and in the
visible range of light, it would only work on objects much thinner than a
single strand of hair.
Useful in nanotechnology
Scientists find this
development exciting because it could prove useful in nanotechnology by
letting light bypass microscopic objects that would otherwise block it.
The discovery could advance the fields of specialty optics and biotechnology, according to the physicists.
This is not the first
time scientists have made an object 'invisible,' but previous methods
have involved hulking devices and more cumbersome methods.
The new cloak is made of
a sheer, handy material that can be applied to many surfaces, even
irregular ones, according to the report.
Light and invisibility
We see things because
light reflects off of them and hits our eyes. Or, in this case,
microwaves bounce off of them and hit a detection device.
Light has properties
that can be manipulated, which is how objects can be rendered invisible.
It can be reflected away, for example. Illusionists such as David
Copperfield can use mirrors to make an object disappear.
Light also refracts --
or breaks -- when it passes through a prism or raindrops, resulting in
the palette of colors we see in a rainbow. It also bends ever so
slightly due to gravity, when it passes by a planet.
Previous attempts at achieving invisibility have involved bending or reflecting light around the object that is meant to vanish.
The mantle cloak takes a new approach.
Light is a wave that can be disturbed. That's what the mantle cloak does.
The cloak's material
It is made by combining
copper tape with polycarbonate, a material commonly used in DVD's and
CDs. The resulting cloak has a miniscule pattern -- like a finely
checkered shirt -- that neutralizes the waves bouncing off of it.
For it to work, the
material's pattern has to be roughly the size of the wavelength of light
to be canceled out. That gives it a tightly limited range of waves it
will work on.
It has no effect on a
vast array of electromagnetic waves, which come in a myriad of sizes.
The light waves we can see make up only a thin sliver of them.
Although the scientists
say the principle behind the cloak could currently only be used to hide
objects from the human eye that are so tiny it can't see them anyhow,
they say it could "pave the way" to the development of advanced
"camouflaging and invisibility."
Microwaves, which the mantle cloak currently does neutralize, are used in radar detectors.
Perhaps the cloak would make a good ingredient in car paint.
Source:CNN
