This is a multi-part message in MIME format.
------=_NextPart_000_0054_01C73436.BD8421A0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Metamaterials Found To Work For Visible Light
Science Daily - For the first time ever, researchers at the U.S. =
Department of Energy's Ames Laboratory have developed a material with a =
negative refractive index for visible light. Ames Laboratory senior =
physicist Costas Soukoulis, working with colleagues in Karlsruhe, =
Germany, designed a silver-based, mesh-like material that marks the =
latest advance in the rapidly evolving field of metamaterials, materials =
that could lead to a wide range of new applications as varied as =
ultrahigh-resolution imaging systems and cloaking devices.
The discovery, detailed in the Jan. 5 issue of Science and the Jan. 1 =
issue of Optic Letters, and noted in the journal Nature, marks a =
significant step forward from existing metamaterials that operate in the =
microwave or far infrared -- but still invisible --regions of the =
spectrum. Those materials, announced this past summer, were heralded as =
the first step in creating an invisibility cloak.
Metamaterials, also known as left-handed materials, are exotic, =
artificially created materials that provide optical properties not found =
in natural materials. Natural materials refract light, or =
electromagnetic radiation, to the right of the incident beam at =
different angles and speeds. However, metamaterials make it possible to =
refract light to the left, or at a negative angle. This backward-bending =
characteristic provides scientists the ability to control light similar =
to the way they use semiconductors to control electricity, which opens a =
wide range of potential applications.
"Left-handed materials may one day lead to the development of a type of =
flat superlens that operates in the visible spectrum," said Soukoulis, =
who is also an Iowa State University Distinguished Professor of Liberal =
Arts and Sciences. "Such a lens would offer superior resolution over =
conventional technology, capturing details much smaller than one =
wavelength of light to vastly improve imaging for materials or =
biomedical applications," such as giving researchers the power to see =
inside a human cell or diagnose disease in a baby still in the womb.
The challenge that Soukoulis and other scientists who work with =
metamaterials face is to fabricate them so that they refract light at =
ever smaller wavelengths. The "fishnet" design developed by Soukoulis' =
group and produced by researchers Stefan Linden and Martin Wegener at =
the University of Karlsruhe was made by etching an array of holes into =
layers of silver and magnesium fluoride on a glass substrate. The holes =
are roughly 100 nanometers wide. For some perspective, a human hair is =
about 100,000 nanometers in diameter.=20
"We have fabricated for the first time a negative-index metamaterial =
with a refractive index of -0.6 at the red end of the visible spectrum =
(wavelength 780 nm)," said Soukoulis. "This is the smallest wavelength =
obtained so far."
While the silver used in the fishnet material offers less resistance =
when subjected to electromagnetic radiation than the gold used in =
earlier materials, energy loss is still a major limiting factor. The =
difficulties in manufacturing materials at such a small scale also limit =
the attempts to harness light at ever smaller wavelengths.
"Right now, the materials we can build at THz and optical wavelengths =
operate in only one direction," Soukoulis said, "but we've still come a =
long ways in the six years since negative-index materials were first =
demonstrated."
"However, for applications to come within reach, several goals need to =
be achieved," he added. "First, reduction of losses by using crystalline =
metals and/or by introducing optically amplifying materials; developing =
three-dimensional isotropic designs rather than planar structures; and =
finding ways of mass producing large-area structures."
The Basic Energy Sciences Office of the DOE's Office of Science funds =
Ames Laboratory's research on metamaterials. Ames Laboratory, which is =
celebrating its 60th anniversary in 2007, is operated for the Department =
of Energy by Iowa State University. The Lab conducts research into =
various areas of national concern, including energy resources, =
high-speed computer design, environmental cleanup and restoration, and =
the synthesis and study of new materials.
Note: This story has been adapted from a news release issued by Ames =
Laboratory.
Source: Ames Laboratory
http://www.sciencedaily.com/releases/2007/01/070104144655.htm
--=20
Posted by
Robert Karl Stonjek
------=_NextPart_000_0054_01C73436.BD8421A0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.3790.1218" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY>
<DIV>
<H1 class=3Dstory><FONT size=3D5>Metamaterials Found To Work For Visible =
Light</FONT></H1><!-- BODY BEGIN -->
<P class=3Dfirst><EM><A style=3D"COLOR: #666; TEXT-DECORATION: none"=20
href=3D"http://www.sciencedaily.com/">Science Daily</A> =97</EM> For the =
first time=20
ever, researchers at the U.S. Department of Energy's Ames Laboratory =
have=20
developed a material with a negative refractive index for visible light. =
Ames=20
Laboratory senior physicist Costas Soukoulis, working with colleagues in =
Karlsruhe, Germany, designed a silver-based, mesh-like material that =
marks the=20
latest advance in the rapidly evolving field of metamaterials, materials =
that=20
could lead to a wide range of new applications as varied as =
ultrahigh-resolution=20
imaging systems and cloaking devices.</P>
<P>The discovery, detailed in the Jan. 5 issue of Science and the Jan. 1 =
issue=20
of Optic Letters, and noted in the journal Nature, marks a significant =
step=20
forward from existing metamaterials that operate in the microwave or far =
infrared -- but still invisible --regions of the spectrum. Those =
materials,=20
announced this past summer, were heralded as the first step in creating =
an=20
invisibility cloak.</P>
<P>Metamaterials, also known as left-handed materials, are exotic, =
artificially=20
created materials that provide optical properties not found in natural=20
materials. Natural materials refract light, or electromagnetic =
radiation, to the=20
right of the incident beam at different angles and speeds. However,=20
metamaterials make it possible to refract light to the left, or at a =
negative=20
angle. This backward-bending characteristic provides scientists the =
ability to=20
control light similar to the way they use semiconductors to control =
electricity,=20
which opens a wide range of potential applications.</P>
<P>"Left-handed materials may one day lead to the development of a type =
of flat=20
superlens that operates in the visible spectrum," said Soukoulis, who is =
also an=20
Iowa State University Distinguished Professor of Liberal Arts and =
Sciences.=20
"Such a lens would offer superior resolution over conventional =
technology,=20
capturing details much smaller than one wavelength of light to vastly =
improve=20
imaging for materials or biomedical applications," such as giving =
researchers=20
the power to see inside a human cell or diagnose disease in a baby still =
in the=20
womb.</P>
<P>The challenge that Soukoulis and other scientists who work with =
metamaterials=20
face is to fabricate them so that they refract light at ever smaller=20
wavelengths. The "fishnet" design developed by Soukoulis' group and =
produced by=20
researchers Stefan Linden and Martin Wegener at the University of =
Karlsruhe was=20
made by etching an array of holes into layers of silver and magnesium =
fluoride=20
on a glass substrate. The holes are roughly 100 nanometers wide. For =
some=20
perspective, a human hair is about 100,000 nanometers in diameter. </P>
<P>"We have fabricated for the first time a negative-index metamaterial =
with a=20
refractive index of -0.6 at the red end of the visible spectrum =
(wavelength 780=20
nm)," said Soukoulis. "This is the smallest wavelength obtained so =
far."</P>
<P>While the silver used in the fishnet material offers less resistance =
when=20
subjected to electromagnetic radiation than the gold used in earlier =
materials,=20
energy loss is still a major limiting factor. The difficulties in =
manufacturing=20
materials at such a small scale also limit the attempts to harness light =
at ever=20
smaller wavelengths.</P>
<P>"Right now, the materials we can build at THz and optical wavelengths =
operate=20
in only one direction," Soukoulis said, "but we've still come a long =
ways in the=20
six years since negative-index materials were first demonstrated."</P>
<P>"However, for applications to come within reach, several goals need =
to be=20
achieved," he added. "First, reduction of losses by using crystalline =
metals=20
and/or by introducing optically amplifying materials; developing=20
three-dimensional isotropic designs rather than planar structures; and =
finding=20
ways of mass producing large-area structures."</P>
<P>The Basic Energy Sciences Office of the DOE's Office of Science funds =
Ames=20
Laboratory's research on metamaterials. Ames Laboratory, which is =
celebrating=20
its 60th anniversary in 2007, is operated for the Department of Energy =
by Iowa=20
State University. The Lab conducts research into various areas of =
national=20
concern, including energy resources, high-speed computer design, =
environmental=20
cleanup and restoration, and the synthesis and study of new =
materials.</P>
<P><EM>Note: This story has been adapted from a news release issued by =
Ames=20
Laboratory.</EM></P><!-- BODY END -->
<DIV style=3D"CLEAR: both"></DIV>
<DIV id=3Dsecond_ad_unit>Source: Ames Laboratory</DIV>
<DIV><A=20
href=3D"http://www.sciencedaily.com/releases/2007/01/070104144655.htm">ht=
tp://www.sciencedaily.com/releases/2007/01/070104144655.htm</A></DIV>
<DIV><BR>-- <BR>Posted by<BR>Robert Karl Stonjek</DIV><!-- Originally =
posted on ScienceDaily 2007-01-09 --></DIV></BODY></HTML>
------=_NextPart_000_0054_01C73436.BD8421A0--
.
|
