TIME - Scientists at UC Berkeley have taken a major step toward making Harry Potter's disguise of choice a reality. They've engineered two new materials — one using a fishnet of metal layers, the other using tiny silver wires — that neither absorb nor reflect light, causing it instead to bend backward. The principle at work is refraction, which is what makes a straw appear bent in a glass of water.
Scientists at the University of California, Berkeley, have for the first time engineered 3-D materials that can reverse the natural direction of visible and near-infrared light, a development that could help form the basis for higher resolution optical imaging, nanocircuits for high-powered computers, and, to the delight of science-fiction and fantasy buffs, cloaking devices that could render objects invisible to the human eye.
Two breakthroughs in the development of metamaterials - composite materials with extraordinary capabilities to bend electromagnetic waves - are reported separately this week in the Aug. 13 advanced online issue of Nature, and in the Aug. 15 issue of Science.
The common thread in such metamaterials is negative refraction. In contrast, all materials found in nature have a positive refractive index, a measure of how much electromagnetic waves are bent when moving from one medium to another.
Other research teams have previously developed metamaterials that function at optical frequencies, but those 2-D materials have been limited to a single monolayer of artificial atoms whose light-bending properties cannot be defined. Thicker, 3-D metamaterials with negative refraction have only been reported at longer microwave wavelengths.
"What we have done is take two very different approaches to the challenge of creating bulk metamaterials that can exhibit negative refraction in optical frequencies," said Xiang Zhang, professor at UC Berkeley's Nanoscale Science and Engineering Center, funded by the National Science Foundation (NSF), and head of the research teams that developed the two new metamaterials. "Both bring us a major step closer to the development of practical applications for metamaterials."
Zhang is also a faculty scientist in the Material Sciences Division at the Lawrence Berkeley National Laboratory.
Transmission measurements of these structures were carried out by the Zhang group at ALS beamline 1.4.3.
See the full news release from UC Berkeley.
Other news stories about this work: August 11: ScienceNow; USA Today; ABC News; Associated Press Video; National Geographic; NPR Radio; The New York Times; CNN; Reuters; BBC News; SF Chronicle; London Times; The Guardian; The Telegraph; Daily Mail; Scientific American; R&D Magazine Feature; VOA News; Popular Mechanics; BBC News; International Herald Tribune; KCBS Radio; KSL Newsradio; Irish Times; The Australian; Los Angeles Times; Time; Shanghai Daily; Chicago Tribune; Boston Globe; Brisbane Times; Sydney Morning Herald; Science News; Slashdot; c|net; Photonics.com; KTVU Television; ABC7; and hundreds more.
Sep 1: Spectroscopy Now.
The ALS hosts students from high school to graduate school and from all over the world. One of our most successful collaborations is the ALS/ENSICAEN internship program, organized by ALS scientist Fred Schlachter and ENSICAEN professor Gilles Ban. ENSICAEN, located in Caen, France, offers engineering degrees in electronics, computer science, and material science and chemistry. "So many students were interested in coming to Berkeley that I had to find other hosts," says Fred.
This summer, six students interned with scientists Wayne Stolte, Alex Aguilar, and Michael Martin. Xavier Joubert and Claire Morichau Beauchant worked with Mike Martin on Beamline 1.4.3. Xavier is with ENSICAEN, Claire is with a similar program at the Ecole Nationale Supérieure de Physique in Grenoble. Xavier worked on two projects to use piezo-driven mirrors to scan the IR beam across the sample for faster mapping capabilities and determined how to make use of an array detector with actuated mirrors to drive the beam to different pixels within the array. Claire worked on a novel method to collect spectral images more rapidly using image compression techniques.
To read the full story, see ALS News Vol 289.
Honing in on graphene electronics with infrared synchrotron radiation
Researchers at the ALS Infrared Beamlines, the University of California at San Diego (UCSD), working with colleagues at Columbia University in New York and the National High Magnetic Field Laboratory in Florida have measured the extraordinary properties of graphene with an accuracy never before achieved. The results confirm many of the strangest features of the unusual material but also reveal significant departures from theoretical predictions. And they point the way to novel practical applications, such as tunable optical modulators for communications and other nanoscale electronics. The researchers report their findings in the June issue of the journal Nature Physics.
"Physicists Reveal Secrets Of Newest Form Of Carbon" 06/10/08: UCSD News Release; ScienceDaily; PhysOrg.com; Genetic Engineering & Biotechnology News; NanoWerk; Xinhua (China); Science Centric; Eureka! Science News; 06/11/08: People's Daily; The Hindu; Thaindian News; NewsLocale; Daily India; Fresh News; HULIQ.com; theCheers.org; LightSources.org; Mathaba; 06/12/08: Chemie.de; Innovations Report;
"Dirac Charge Dynamics in Graphene by Infrared Spectroscopy." ALS News 292, Oct 29, 2008.
The Department of Energy's Office of Science has honored five Berkeley Lab researchers — Manfred Auer and Danielle Jorgens, (Life Sciences), Michael Martin (ALS), Howard Matis (Nuclear Science) and Margaret Torn (Earth Sciences) — as Outstanding Mentors for their work with students, coordinated through the Lab’s Center for Science and Engineering Education (CSEE) last summer. "The role of mentors is absolutely essential in preparing the next generation of scientists and engineers," says Susan Brady, head of CSEE. “We hope more Lab scientists will consider serving as mentors this summer.” Today at LBNL, Mar 11, 2008.
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