INVISIBILITY 25
present, the smallest components that one can create with this etching
process are about 30 nm (or about 150 atoms across).
A milestone in the quest for invisibility came when this silicon
wafer etching technology was used by a group of scientists to create
the first metamaterial that operates in the visible range of light. Scientists in Germany and at the U.S. Department of Energy announced in
early 2007 that, for the first time in history, they had fabricated a metamaterial that worked for red light. The "impossible" had been achieved
in a remarkably short time.
Physicist Costas Soukoulis of the Ames Laboratory in Iowa, with
Stefan Linden, Martin Wegener, and Gunnar Dolling of the University
of Karlsruhe, Germany, were able to create a metamaterial that had an
index of -.6 for red light, at a wavelength of 780 nm. (Previously, the
world record for radiation bent by a metamaterial was 1,400 nm,
which put it outside the range of visible light, in the range of infrared.)
The scientists first started with a glass sheet, and then deposited a
thin coating of silver, magnesium fluoride, and then another layer of
silver, forming a "sandwich" of fluoride that was only 100 nm thick.
Then, using standard etching techniques, they created a large array of
microscopic square holes in the sandwich, creating a grid pattern resembling a fishnet. (The holes are only 100 nm wide, much smaller
than the wavelength of red light.) Then they passed a red light beam
through the material and measured its index, which was -.6.
These physicists foresee many applications of this technology.
Metamaterials "may one day lead to the development of a type of flat
superlens that operates in the visible spectrum," says Dr. Soukoulis.
"Such a lens would offer superior resolution over conventional technology, capturing details much smaller than one wavelength of light."
The immediate application of such a "superlens" would be to photograph microscopic objects with unparalleled clarity, such as the inside
of a living human cell, or to diagnose diseases in a baby inside the
womb. Ideally one would be able to obtain photographs of the components of a DNA molecule without having to use clumsy X-ray crystallography.
So far these scientists have demonstrated a negative index of re-
present, the smallest components that one can create with this etching
process are about 30 nm (or about 150 atoms across).
A milestone in the quest for invisibility came when this silicon
wafer etching technology was used by a group of scientists to create
the first metamaterial that operates in the visible range of light. Scientists in Germany and at the U.S. Department of Energy announced in
early 2007 that, for the first time in history, they had fabricated a metamaterial that worked for red light. The "impossible" had been achieved
in a remarkably short time.
Physicist Costas Soukoulis of the Ames Laboratory in Iowa, with
Stefan Linden, Martin Wegener, and Gunnar Dolling of the University
of Karlsruhe, Germany, were able to create a metamaterial that had an
index of -.6 for red light, at a wavelength of 780 nm. (Previously, the
world record for radiation bent by a metamaterial was 1,400 nm,
which put it outside the range of visible light, in the range of infrared.)
The scientists first started with a glass sheet, and then deposited a
thin coating of silver, magnesium fluoride, and then another layer of
silver, forming a "sandwich" of fluoride that was only 100 nm thick.
Then, using standard etching techniques, they created a large array of
microscopic square holes in the sandwich, creating a grid pattern resembling a fishnet. (The holes are only 100 nm wide, much smaller
than the wavelength of red light.) Then they passed a red light beam
through the material and measured its index, which was -.6.
These physicists foresee many applications of this technology.
Metamaterials "may one day lead to the development of a type of flat
superlens that operates in the visible spectrum," says Dr. Soukoulis.
"Such a lens would offer superior resolution over conventional technology, capturing details much smaller than one wavelength of light."
The immediate application of such a "superlens" would be to photograph microscopic objects with unparalleled clarity, such as the inside
of a living human cell, or to diagnose diseases in a baby inside the
womb. Ideally one would be able to obtain photographs of the components of a DNA molecule without having to use clumsy X-ray crystallography.
So far these scientists have demonstrated a negative index of re-