A team of researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory has developed the new “multilayer Laue lens”. This lens focuses high-energy X-rays so tightly they can detect objects as small as 15 nanometers in size and is in principle capable of focusing to well below 10 nanometers. This approach doubles the resolution over existing lenses, and future advancements could increase resolution by 10 times. From left to right: Bing Shi, Brian Stephenson, Jörg Maser, Chian Liu, Lisa Gades. Image courtesy of Argonne National Laboratory |
More
affordable and efficient solar cells, batteries and lighting systems
could result from a new x-ray lens that will let scientists study the
nanoscale in greater detail than ever before.
A
team of researchers at the U.S. Department of Energy’s (DOE) Argonne
National Laboratory has developed the new “multilayer Laue lens”. This
lens focuses high-energy X-rays so tightly they can detect objects as
small as 15 nm in size and is in principle capable of focusing to well
below 10 nm. This approach doubles the resolution over existing lenses,
and future advancements could increase resolution by 10 times.
Understanding,
imaging and manipulating the physical world at the nanoscale is
critical to designing materials, devices and technologies that impact
our daily lives. To aid in this effort, Argonne’s Advanced Photon Source
(APS) and Center for Nanoscale Materials (CNM) partnered to improve
lens capabilities.
“There’s
a big need to look into the nanoscale world,” said Lahsen Assoufid,
Optics Group Leader at the APS. “Availability of this new type of X-ray
lens will definitely open new windows into to nanoscale science. “
If
you want to look at a material closely—really closely—hard X-rays like
those produced at the APS are the answer. The APS provides some of the
nation’s brightest beams of X-rays for research; more than 3,500
scientists from industry, academia and national laboratories conducted
experiments there last year. These extremely intense and focused X-rays
allow scientists to peer into the depths of the nanoworld by focusing
the photons on a single small area.
“With
this lens, you will be able to see individual nanoparticles,” said
Argonne physicist Jörg Maser, who conducts research at the APS and CNM.”
Coupled with the X-rays at the APS, you can detect materials down to
the level of 10 atoms in a complex environment.”
The
team designed the new lens to improve the focusing of hard X-rays. The
lens is crafted by depositing thousands of alternating layers of silicon
and tungsten silicide one by one, which are then polished down to just
10 ?m thin.
“One
of the major 21st century challenges we face is energy,” Maser said.
“For example, solar energy is not yet cost-effective on a
dollar-per-kilowatt-hour level. In order to drive the price down to $1
per kilowatt, we need solar cells that are more efficient and made from
less expensive materials. To get there, we need a better understanding
of the defects that occur while solar cells are manufactured.”
By
watching solar cells as they are manufactured and identifying where the
defects occur, scientists hope to improve the quality of manufactured
cells.
The
Argonne team began work on the lens in 2003, working out the complex
calculations to predict how—and whether—it would work. Then they needed
to demonstrate the idea, perfect a prototype and test the lens. A set of
the lenses is now in use at the APS, and more are being fabricated.
Brookhaven National Laboratory’s x-ray synchrotron has begun a strong
research effort in fabricating advanced multilayer Laue lenses, Maser
said, and groups in Japan and Europe have begun to develop similar
systems.
In
the near future, the team is expecting to incorporate the new lenses
into microelectromechanical systems, or MEMS: mechanical structures with
micrometer-size movable parts. MEMS can be used to precisely position
and control these new lenses. Particularly attractive is the possibility
of automatically focusing the lenses during experiments, and the
ability to scan the X-rays very quickly across samples. This research
takes place collaboratively between the APS and Argonne’s Center for
Nanoscale Materials.
Two dimensional hard x-ray nanofocusing with crossed multilayer Laue lenses
