Professor Martin Booth read for a degree in Engineering Science at Hertford College, Oxford, from 1993-7. His doctoral work in adaptive optics for confocal microscopy took place in the Department of Engineering Science at the University of Oxford from 1997-2001, during which time he was also a member of Jesus College.
In 2001, Martin was elected to a Junior Research Fellowship at Christ Church and in 2003 was appointed a Royal Academy of Engineering/EPSRC Research Fellow. In 2007 he was awarded a five-year EPSRC Advanced Research Fellowship and was concurrently elected to a Hugh Price Fellowship at Jesus College.
He became Professor of Engineering Science and Senior Research Fellow at Jesus College in 2014. He also holds a College Lecturership at Lincoln College. His current research interests centre on the development of new dynamic optical methods for applications ranging from biomedical imaging to laser-based manufacturing.
The imaging quality of a high-resolution microscope is severely compromised when aberrations are present in the optical system. These aberrations lead to reduced signal level and degraded lateral and, more significantly, axial resolution. Often aberrations are introduced not only by misalignment of optical components in the microscope but also by variations in refractive index of the specimen itself. Martin's group are developing adaptive optics systems to overcome these limitations. They have implemented adaptive optics in a range of microscopes and have demonstrated the benefits of aberration correction, showing improved contrast and resolution when imaging deep within specimens.
Many applications of high resolution microscopes are in the biological sciences. Research includes advances in the technology of confocal and two-photon fluorescence microscopes, harmonic generation microscopes and other high resolution methods. This group has numerous collaborations with other researchers across Oxford for applications including cell biology, developmental biology and neuroscience.
Superresolution microscopy - or nanoscopy - enables visualisation of objects much smaller than the physical diffraction limit of light. These methods are regularly used in biological applications to resolve features in the tens of nanometres range. They are working on new methods for nanoscopy and in particular on the development of dynamic optics to extend the usability of this approach in practical applications. Their work includes technology and applications for stimulated emission depletion (STED) microscopy, single molecule switching methods (such as STORM, PALM, etc.) and structured illumination microscopy.
The high intensity in a tightly focussed laser beam can cause material modification that is well confined within three-dimensions. This provides the capability of fabricating 3D structures within transparent substrates. However, this usually requires focussing into high refractive index materials, which leads to significant aberrations that distort the focus. Since the size of fabricated features depends upon the shape of the focus, aberrations must be corrected for precision to be maintained. They are developing adaptive optics for the measurement and correction of these aberrations for machining applications.
Many direct laser writing systems rely upon the sequential exposure of the workpiece in a point-by-point fashion. This permits high precision fabrication, but at the expense of long processing times, especially when working in three dimensions. They have developed dynamic optical methods, using liquid crystal spatial light modulators to parallelise the laser writing process by creating multiple, individually controllable foci. This has been combined with aberration correction to maintain precision throughout a three-dimensional
Diamond is an important material with many properties that make it useful across a wide range of engineering and scientific applications. They are developing methods for the processing of diamond and various applications ranging from quantum optics to biological sensing. In particular, adaptive optical laser fabrication methods enable the creation of structures deep within diamond crystals, including graphitic conductors. They are also using crystallographic defects, such as the nitrogen-vacancy colour centre, as electromagnetic sensors for detection of neural activity. This is a particularly powerful method when combined with super-resolution microscopy.
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