LASER
Joining
TECHNOLOGY
the dots
Medical lasers that exploit the properties of quantum dots could revolutionise
the treatment of everything from acne to cancer. Stuart Nathan reports
THE ULTIMATE icon of high technology,
lasers, are now a part of everyday life as
essential components in audio-visual
systems. But despite their ubiquity,
lasers still occupy a cutting edge position
in every sense. And in the medical field, a
flurry of recent developments is set to
give rise to a new generation of powerful,
versatile and, above all, affordable
devices.
The EU is pumping €10m (almost £8m)
into these products, via a project called
FAST-DOT. Based at Dundee University,
and involving 18 collaborators in
academia and industry, the project aims
22
Quick cut: very
fast pulsed energy
is required for
laser surgery
to develop laser systems about the size
of a matchbox, capable of performing
the same functions as a fixed, heavy,
shoebox-sized laser — and more — for a
tenth of the cost and consuming an
even smaller fraction of the energy.
Potential applications range from
precise and bleeding-free surgery to
analysis of biological samples.
‘This project will revolutionise the
use of lasers in the biomedical field,’
claimed research director Edik
Rafailov of Dundee’s photonics and
nanoscience group.
At the centre of these developments
is a relatively new type of laser based
on semiconductor trickery. Whereas
most lasers up to now have used a
solid chunk of material, a bulk liquid
or gas as the medium which produces
laser energy, these new devices are
based around a structure called a
quantum dot — a custom-built
crystal, pieced together atom by
atom, to form what is in effect a cage to
hold electrons.
When semiconductors conduct
electricity, the electrons that can move
around in the structure have a series of
energies known as an energy band.
the EnGIneeR 1–14 SEPTEMBER 2008
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