Classical and quantum optics
Research
teams in the School are active in the optics fields in
areas ranging from the fundamentals of the interactions
between light and atoms, through to the development of
new optical instrumentation to fit specific industrial
needs. An example of the former is the use of tunable-diode-lasers
to slow down (cool) and trap atoms at temperatures close
to absolute zero for long periods (see diagram). This
then allows these atoms and their interaction with light
to be studied closely. Other areas include:
- exploiting quantum interference between different atomic states within the same atom to switch off absorption
-
laser modes with orbital angular momentum
- the generation and investigation of single-cycle optical pulses.
At
the more applied end, we show here an example of a novel
optical instrument developed at St Andrews. This allows
the spectrum of a light source to be measured accurately,
robustly and quickly, and with a small, inexpensive instrument.
The optical elements, which include polarisers and birefringent
crystals, are sandwiched in front of a TV camera. The
interference fringes that are produced on the camera are
analysed by the computer to determine the spectrum. This
system is now being used to detect toxic gases at the
parts per million and parts per billion levels.
We
have also developed optical systems for use in hospitals.
The system on the left uses a phosphor coated bulb to
illuminate skin with deep blue light. A filtered
camera monitors the fluorescence, which may be used to
detect skin cancer. This system was developed in
collaboration with physicists at Glasgow and clinicians
at Dundee's Ninewells hospital.
Our work in this area of "biophotonics" is expanding, with a wide range of work being carried out in collaboration with clinicians, biologists, and chemists.
Bringing together cutting edge theory and experiment we have teams working in the field of quantum optical information processing. This may open up possibilities of totally secure optical communication systems, based on the fundamental aspects of quantum mechanics.
Other optical and laser instrumentation is being developed for applications in medical imaging, underwater imaging, inspection of surfaces, and micro-manipulation of tiny particles.
27.7.05
