One of our core strengths is in optical coherence tomography (OCT); we were at the forefront of developments in en face OCT and combining OCT with scanning laser ophthalmoscopy, and more recently developed master-slave OCT for high-speed processing of raw Fourier domain data. We have worked with a wide range of collaborators to develop ophthalmic and wider medical and industrial applications of OCT, including to areas such as art conservation. More recently, we have been developing handheld and endoscopic OCT and multi-modal imaging systems, and hold a major grant to develop OCT and fluorescence imaging systems for robot-guided intervention and surgery. We also have projects on photoacoustic imaging and endoscopic microscopy.
Optical coherence tomography systems and devices
The AOG has made significant contributions to the development of optical coherence tomography (OCT) and to en face OCT in particular. We have built a wide range of time and Fourier domain OCT systems, including at 820, 1050 and 1300 nm. We have worked on adaptive optics for enhanced resolution as well as techniques for simultaneous multi-depth imaging, dynamic focus, phase sensitive OCT, polarisation-sensitive OCT, full-field OCT, and speckle reduction. Developments also include new swept sources for Fourier domain imaging. We have a strong interest in high-speed OCT data processing – we were part of an NVIDIA GPU research centre – and the master-slave OCT image reconstruction technique was recently developed at Kent. In collaboration with NKT Photonics, via a European Industrial Doctorate (UBAPHODESA), we are working on large bandwidth optical sources and their applications for multi-modal optical imaging.
Applications of optical coherence tomography
We have worked with collaborators to develop applications of OCT for biomedical applications, including for imaging the retina, cornea, larynx, skin, basal cell carcinoma, the tympanic membrane, neuronal tissue, embryos and in dentistry, as well as non-medical applications such as art conservation. Our systems have been deployed to several hospitals for trials, including Northwick Park Hospital in London and as far afield as the New York Eye and Ear Infirmary.
Multi-modal optical imaging
We have combined OCT and other imaging techniques to achieve multi-modality biomedical imaging. The first combined scanning laser opthalmoscope (confocal microscopy for the eye) and optical coherence tomography (SLO/OCT) was patented at Kent by Adrian Podoleanu and David Jackson in 1998 (US Patent 5975697). The technology was exclusively licensed to Ophthalmic Technology Inc (OTI), Canada. Work at Kent later added a fluorescence channel to the system, allowing simultaneous OCT, SLO and indocyanine green (ICG) fluorescence imaging of the retina. We have also used combined fluorescence and OCT imaging for studying specimens such as Drosophila melanogaster larval heart. Recently we have been working to combine photoacoustic imaging with OCT using high-energy supercontinuum sources from NKT Photonics.
Handheld and endoscopic imaging
We have developed a research programme in miniaturised handheld and endoscopic OCT and fluorescence imaging systems for minimally invasive medical diagnostics. For example, in collaboration with Northwick Park Hospital and the Institute of Applied Physics in Russia we developed a forward-viewing OCT probe combined with a fibre bundle endoscope for dual-mode ear, nose and throat (ENT) imaging. We are now developing robot-guided OCT and fluorescence imaging probes for the lung, as part of the REBOT project in collaboration with Imperial College London. We are also working on endoscopic and needle-based fluorescence microscopes.
Optical measurement and sensing
The AOG has a long history in optical sensing and measurement for example in structural health monitoring, distributed sensing, metrology, and medical sensing, as well as in high-speed microwave photonics and optical correlators. Recently, we demonstrated a coherence-gated wavefront sensor for depth-resolved measurements of wavefront aberrations.