Scientists have taken the first ever snapshot of an atom's
shadow—the smallest ever photographed using visible light. The imaging
technique could have big implications for genetic research and
cryptography, researchers say.
The pioneering shutterbugs used an electrical field to suspend a
charged atom, or ion, of the element ytterbium in a vacuum chamber. They
then shot a laser beam—about a thousand times wider than the atom—at
the ytterbium.
The ytterbium atom absorbed a tiny portion of the
light, and the resulting shadow was magnified by a lens attached to a
microscope, then recorded via a digital camera sensor.
The team used ytterbium because they knew they could create lasers of the right color to be strongly absorbed by the element.
"Each
element responds to different specific wavelengths ... so we would need
different laser systems to use this technique on a different atom,"
said study leader Dave Kielpinski.
Atoms, he added, are the smallest things that can be seen in visible
light, and though the team's shadow shots are unprecedented, atoms themselves have been photographed before.
Since
capturing the unique picture, the team has been refining their
technique, creating (as yet unreleased) photos of ytterbium shadows
twice as dark as in the above image, said Kielpinski, a physicist at
Australia's Griffith University.
The group is also working on
increasing the resolution of their images, so that it might one day be
possible to see how the electrons orbiting an atom affect the shape of
its shadow.
The
shadow-imaging technique could one day enable scientists to study DNA
inside living cells by shining a laser at them and observing patterns of
light absorption, the researchers say. Current techniques—involving
attaching special molecules to DNA—are potentially harmful to cells.
The
technology might also one day be harnessed to send information across
"quantum cryptography networks," which would use single atoms as
data-storage devices and quantum physics to guarantee privacy,
Kielpinski said.
"Our work gives a new way to get light to talk to
single atoms," he added, "so we can cook up new protocols for these
storage nodes."
The atom-shadow research is detailed in the July 3 issue of the journal Nature Communications.
http://news.nationalgeographic.com/news/2012/07/120710-first-picture-atom-shadow-photograph-science-nature-smallest/
No comments:
Post a Comment