Professor Xiang Zhang
The Scientific American article Light bent the wrong way — can an invisibility cloak be far behind? said
Researchers have taken the next step on the road to constructing a cloak of invisibility or a powerful “superlens” capable of capturing fine details undetectable to current lenses. A group from the University of California, Berkeley, this week is publishing the first demonstrations of materials capable of bending visible or near-visible light the “wrong” way in three dimensions.
Both are examples of metamaterials — specially designed structures that cause light to do things it normally wouldn’t in this case, bending backward, an effect called negative refraction. Researchers have built metamaterials capable of negatively refracting microwaves, but despite some successes bending visible light in two dimensions, they’ve had a harder time making three-dimensional versions.
In a study to be published in Nature, the Berkeley group led by Xiang Zhang, bent red light using a fishnet-shaped stack of 21 layers of silver and magnesium fluoride, each a few tens of nanometers thick (see diagram). (One nanometer is a billionth of a meter.) The group will also report in Science that it bent near-infrared light using a thinner sheet of aluminum oxide containing silver nanowires. The researchers believe the second material ought to work on red light as well.
Xiang Zhang, Ph.D.
is Chancellor’s Professor at UC Berkeley and the Director
of the NSF Nano-scale Science and Engineering Center (NSEC) which
includes
Berkeley-
Stanford-UCLA-UCSD-UNCC. He also serves as Director of the Department of
Defense
MURI Center on Metamaterials and Devices that includes
Berkeley-MIT-UCLA-UCSD-Duke-
Imperial College (UK).
Xiang’s current research focused on nano-scale science and
technology, meta-materials, nano-photonics, and bio-technologies. He has
published more
than 80 technical papers including publications in Science and Nature
Materials. He has
given over 80 invited or keynote talks at international conferences and
institutions.
He is on the editorial boards of three journals. He is a
co-chair of NSF
Nanoscale Science and Engineering Annual Grantee Conference in
2004–2005 and Chair of
Technical Program of IEEE 2nd International Conference on Micro and Nano
Engineered
and Molecular Systems in 2007.
His research has been selected to be one of Top Ten
Nanotechnology Breakthroughs in 2005, and Fast Breaking Papers, as one
of the most
cited recent papers in Physics in 2006, and R&D Magazine’s “Top 25: The
Most Innovative
Products” of 2006. He was selected as a Finalist for the 2005 Small
Times
Magazine 2005
Small Tech Best Researcher Award. His research is frequently featured
by media such
as MRS Bulletin (Materials Research Society), Laser Focus World,
Photonics Spectra,
Materials Today, Physics Web, San Jose Business Journal, R&D Magazine,
as well as
international media including BBC News, UK, Better Humans,
Canada, and The
Hindu, India.
Xiang is a recipient of the NSF CAREER Award (1997), Engineering
Foundation
Award (1997), SME Dell K. Allen Outstanding Young Manufacturing Engineer
Award
(1998), and the ONR Young Investigator Award (1999). He was nominated in
2004
for the
Millennium Technology Prize, the world’s largest technology award. He
was
selected as a
“Distinguished Lecturer” at University of Texas at Austin in 2004 and
SEMETECH in
2005.
He coauthored
Creation of a magnetic plasmon polariton through strong coupling
between
an artificial magnetic
atom and the defect state in a defective multilayer microcavity,
Three Dimensional Optical Metamaterial Exhibiting Negative Refractive
Index,
A hybrid plasmonic waveguide for subwavelength confinement and long
range propagation,
Plasmon-Induced Transparency in Metamaterials,
Superlenses to overcome the diffraction limit,
Cloaking of Matter Waves,
Magnetic plasmon modes in periodic chains of nanosandwiches,
and
Super-Resolution Imaging by Random Adsorbed Molecule Probes.
Read the
full list of his publications!
Xiang earned his Ph.D. in Mechanical Engineering from UC Berkeley
(1996)
and his MS/BS in Physics from Nanjing University, China.
He was an
assistant
professor at Pennsylvania State University (1996–1999), and associate
professor (1999–2003) and full professor (2003–2004) at UCLA prior
to joining the
Berkeley faculty in 2004. He
is also a member of the NASA Institute of Cell Mimetic Space Exploration
(CMISE) and
member of the Berkeley Nanoscience and Nanotechnology Institute (BNNI).
Watch Xiang on
CNN.
Read
Promising new metamaterial could transform ultrasound
imaging,
Goal of nanoscale optical imaging gets boost with new
hyperlens, and
UC Berkeley Researchers Look to Shrink Optics by “Squeezing”
Light.