The following document (pr0009) is now available =
from the NSF Online Document System
Title: Physicists Produce 'Left-Handed' Composite Materials
Type: News Releases
Subtype: Math/Physical Sciences =
It may be found at:
http://www.nsf.gov/cgi-bin/getpub?pr0009
Full text follows.
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Title: Physicists Produce "Left-Handed" Composite Materials
Date: March 21, 2000
Embargoed until 1 p.m.EST
Media contact:
March 21, 2000
Amber Jones
NSF 00-9
(703)306-1070/aljones@nsf.gov
Program contact:
Carmen Huber
(703)306-1996/chuber@nsf.gov
PHYSICISTS PRODUCE "LEFT-HANDED" COMPOSITE MATERIALS
Physicists supported by the National Science Foundation (NSF) have
produced a new class of composite materials with physical properties
that scientists theorized might be possible, but had never before been
produced. The materials are called "left-handed" because they reverse
many of the physical properties observed in ordinary materials in
response to electromagnetic radiation.
Lead scientists Sheldon Schultz and David Smith of the University
of California at San Diego will announce their findings today at a
meeting of the American Physical Society in Minneapolis, Minn. and
publish them in a future issue of Physical Review Letters.
The new class of materials has the ability to reverse properties
such as the Doppler effect, the principle that changes the frequency of
waves as the source of the waves moves. Thus, a train whistle sounds
higher in pitch as the train approaches and lower as the train recedes.
Maxwell's equations, which describe the relationship between magnetic
and electric fields, suggest that microwave radiation or light would
show the opposite effect in this new class of materials, shifting to
lower frequencies as the source approaches.
Similarly, Maxwell's equations suggest that a lens made of such
materials, instead of dispersing electromagnetic radiation as usual,
would focus it as it passes through.
"If these effects turn out to be possible at optical frequencies,
this material would have the crazy property that a flashlight shining on
a slab can focus the light at a point on the other side," said Schultz.
The scientists demonstrated the ability to reverse these properties
by beaming microwave radiation through a composite material produced
from a series of thin copper rings and ordinary copper wire strung
parallel to the rings. Their results verified the composite had negative
electric permittivity and negative magnetic permeability. In most known
materials in nature, these qualities are positive.
The composite created by the team is among a new class of materials
called "metamaterials," in which the way two or more materials are
mixed, or arranged, at a very fine level can affect the electromagnetic
properties of the resulting composite.
Ultimately, the development of this new class of lefthanded
metamaterials, which was financed by NSF and the Department of Energy,
could have applications in areas such as microwave transmissions,
antennae design, and optical components.
-NSF-
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