Dynamic Optics and Photonics Group research

Adaptive Optics for Microscopy

Devices that use light are integral to scientific, medical, and engineering fields. Familiar examples include microscopes, telescopes, lasers, and medical imaging technologies. However, their usefulness can be limited by distortions in light as it passes through the optical system. This can happen because of intrinsic limitations of the optical system or misalignment within it, as well as structural variations inside a sample. This light distortion causes downstream problems. In microscopes, it reduces the detail that can be seen in the image and introduces errors such as vignette effects, loss of contrast, or noise. In laser technologies, a focused laser beam loses its precision.

Adaptive optics (AO) provides a solution to these problems by compensating for light distortion. In optical systems fitted with adaptive optics devices, light is manipulated on its journey so that distortions are corrected. Measurements of the nature and extent of the distortions are used to inform tailored interventions that correct them. A number of different adaptive optics technologies are actively researched by the DOP group.

Adaptive optics for high-resolution imaging 

Karen M. Hampson, Raphaël Turcotte, Donald T. Miller, Kazuhiro Kurokawa, Jared R. Males, Na Ji & MJ Booth. Nature Reviews Methods Primers 1 (68), 1-26 (2021)

Adaptive optical microscopy: the ongoing quest for the perfect image 

M. J. Booth Light: Science & Applications 3 e165 (2014).

Biological Microscopy

Many applications of our high resolution microscopes are in the biological sciences.  Our research includes advances in the technology of confocal and two-photon fluorescence microscopes, harmonic generation microscopes and other high resolution methods.  Applications have included cell biology, developmental biology and neuroscience. Through collaboration with colleagues in the Centre for Neural Circuits and Behaviour, we have particular interest in advancing optical methods for the investigation of neural activity in fruit fly brains.

Superresolution Microscopy

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. We 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. Our work includes technology and applications for stimulated emission depletion (STED) microscopy, single molecule switching methods (such as STORM, PALM, GSDIM) and structured illumination microscopy.

Adaptive Laser Fabrication

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. We are developing adaptive optics for the measurement and correction of these aberrations for machining applications.

Dynamic Parallel Laser Machining

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. We 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 structure.

Diamond Photonics

Diamond is an important material with many properties that make it useful across a wide range of engineering and scientific applications. We 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. We 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.