The resulting phenomenon breaks the
old rules, creating beams of light that reflect and refract in arbitrary ways, depending upon the surface pattern.
“This amazing design freedom allows
us to shape the reflected and refracted
beams in arbitrary ways so that reflection
and refraction phenomena that never occur
in nature can be observed,” Capasso said.
“For example, a light coming in at an
angle can be reflected toward the light
source, and, paradoxically, there is an
incident angle beyond which light is not
reflected.”
The team is working on a variety of pla-
nar optical components based on the con-
cept of interfacial phase discontinuities
such as planar lenses, which could focus
an image without curving it. This would
eliminate the need for compound lenses
to correct aberrations, and birefringent
interfaces.
IR camera senses hot spots to aid firefighters, military pilots
ORLANDO, Fla. – Firefighters and military pilots often use very cold, cumbersome infrared devices to detect hot spots
and see through smoke, but a technology
that uses gallium nitride (GaN) could
eliminate the need for those conventional
instruments.
Researchers at the University of Central
Florida, led by professors David Hagan
and Eric Van Stryland, have discovered
that GaN – currently used to read Blu-ray
DVDs – could offer an alternative to expensive liquid nitrogen, which boils at
;200 °C.
Although much more research is
needed, Hagan and Van Stryland believe
that infrared sensors on military airplanes
or lightweight cameras could be possible
applications for their technology. Infrared
detection and other thermal imaging sys-
tems are usually based on mercury cad-
mium telluride (MCT). Researchers have
long wanted to see if GaN could detect in-
frared light and produce results similar to
those achieved with MCT detectors.
Professor David Hagan, above, and professor Eric
Van Stryland, both of the University of Central
Florida, have found that gallium nitride could replace
liquid nitrogen to reduce the size of infrared detectors. Courtesy of the University of Central Florida.
Organic electronics printed on CDs, DVDs
LOS ANGELES – A new patterning technique uses commercially available technology to print conducting polymers using
an infrared laser onto standard CDs and
DVDs, a feat that could propel current
proof-of-concept organic devices – organic LEDs, thin-film transistors and
microactuators – into large-scale manufacturing.
Developed by engineers at Hewlett-
Packard, LightScribe uses the infrared
laser inside a CD/DVD drive to record
data onto a CD or DVD as well as to
print labels containing text and images
onto the surface of the disks. To make
these labels, the laser pulses up and down
to chemically activate a specialized dye
coating on the disk’s surface.
Lithography
“Electronic flexible organics can even-
tually replace, if not be complementary to,
metal base electronics, but in order to help
these new types of materials achieve this
goal, we still require a simple and inex-
pensive lithography technique,” said
Veronica Strong, a UCLA doctoral candi-
date. “We ideally wanted to develop a
simple lithography technique that is not
only comparable to other more elaborate
methods, but that also does not require
expensive masks, additional processing,
expensive materials or even cleanroom
operations.”
The generated heat “laser welds,” or
cross-links, the molecular chains and
supramolecular fibers together to change
the surface morphology of a small area of
the polymer. Upon completion of the laser
