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One of the group's main interests is the medical imaging technique of
optical coherence tomography.
OCT requires fast scanning optical delay lines, and we have
investigated one technology for producing up to 35 millimetres of
equivalent delay at 50 metres per second via the optical frequency
domain.
Like ultrasound, OCT images are corrupted by speckle, which can be
static or moving. Moving speckle is known to be useful, but we have
shown that even static speckle may contain useful information.
Resolution at the micron level is called ultrahigh-resolution OCT.
Limits on what can be attained are set by various phenomena. We have
been particularly interested in the fundamental limits set by
dispersion and absorption in tissue.
Our interest in coherent optical techniques extends to a branch of
holography, Fourier holography. We are using
single digital holograms to characterise microstructure in
biological samples over large fields of view.
Our interests in microscopy have led us to also become interested in
fluorescence and other nonlinear optical microscopy techniques, as
well as how deep tissue imaging may be improved in general.
This research extends OCT usage to endoscopic scanning of large-scale
hollow organs. Specifically, we have developed an endoscopic OCT probe
to map the 3-D shape and dynamics of the upper airway, including during
sleep, for sleep apnoea research.
We have also actively investigated diffuse light propagation in skin
motivated by early in vivo detection of melanoma. We have mainly
studied fibre-optic probes based on the diffuse reflectance
spectroscopy of white light.
In carrying out our research, we have built a lot of instruments
comprising optical assemblies, photonic circuits, electronics, data
acquisition and display systems, some of which are featured here.
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