vision technology could become extremely precise thanks
to an inexpensive water-based material capable of
boosting particles of light in the infrared spectrum,
say University of Toronto researchers. The material
has the potential to enhance infrared images tenfold
by coating lenses with a film a 10th of a millimetre
thick and powering the material with a laser.
a study published the January issue of the journal
Optics Letters, U of T professors Ted Sargent and
Eugenia Kumacheva and colleagues produced optical
gain - boosting the power in a beam of light the way
a stereo boosts electrical signals - using nanometre-sized
particles originally suspended in water. The material
can be coated onto computer chips, sprayed onto windows
and painted onto flexible fabrics to reveal a new
infrared world -- featuring colours with wavelengths
longer than the human eye can see.
infrared is the wavelength used to send billions of
bits of information over thousands of kilometres in
fibre-optic cables," says Sargent, a professor
at U of T's Edward S. Rogers Sr. Department of Electrical
and Computer Engineering. "Not only does it enable
night vision in antiterrorism and search and rescue
but it may be used to detect cancer in the first cells
to become malignant because living tissue is transparent
in certain colours in the infrared."
professor Eugenia Kumacheva, the Canada Research Chair
in Advanced Polymer Materials, and her team created
quantum dots - nanometre-sized particles of the semiconductor
lead sulfide - which produce light at carefully chosen
infrared wavelengths. Kumacheva and her team invented
a simple, one-stage, water-based synthesis that produced
ready-to-use quantum dots.
engineers then made thin, smooth films out of Kumacheva's
materials by depositing a drop of water containing
the nanoparticles onto a piece of glass and simply
letting it dry. "When we used intense lasers
to excite the nanomaterial, we found that the film
could double the power of light in a propagating beam
every 30 microns - about a thousandth of an inch,"
says Sargent, the Nortel Networks - Canada Research
Chair in Emerging Technologies. Amplifying light is
necessary for making a laser, for boosting signals
on an optical communications chip and for enhancing
infrared images in biological and antiterrorism applications.
findings complement a breakthrough also made by Sargent
and colleagues that was reported in Nature Materials
Jan. 9. The team reported a paintable material that
for the first time could sense light and harness the
sun's energy at tailored wavelengths in the infrared.
"The field of spray-on infrared nanotechnology
is leaping ahead week-by-week," said Sargent.
"The Jan. 9 discovery senses and harvests infrared
light; today's boosts it. Applying these paintable
infrared materials is splashing open a new palette:
colouring our world using the shades we cannot see,
but which power the Internet, reveal warm objects
against a cold background and allow non-invasive diagnosis
before disease has the chance to progress."
members of the U of T research team are Vlad Sukhovatkin,
Sergei Musikhin, Sam Cauchi and Luda Bakueva of electrical
and computer engineering and Ivan Gorelikov of chemistry.
The study was funded by the Science and Engineering
Research Canada (NSERC) under its NanoInnovation Platform
and also by the Canada Research Chairs Program, the
Canada Foundation for Innovation and the Ontario Innovation
Sargent Eugenia Kumacheva
Electrical and Computer Engineering Department of
U of T Public Affairs