Computational microscopy

Diffraction fundamentally limits the ability to resolve images, but by isolating point emitters, one can image at greater precision than the diffraction limit would suggest. We extend this principle to 3D by engineering the point spread function (PSF) of a microscope into Airy beams. This allows for fluorescent single molecule images to be taken at an extended depth of field, in 3D, at super-resolution.  We have utilised this technique for volumetric reconstruction, and to map the blood flow of zebrafish in 3D. We have also developed the Twin-Airy PSF alongside some novel deconvolution algorithms for localisation, allowing for 3D single molecule images to be taken at higher packing densities than conventional techniques. 

 

 

 

 

 

New generation SPAD (Single photon Avalanche Detector) arrays facilitate the ability to measure the arrival time of detected photons with an accuracy of <50ps in widefield imaging applications. In ICG we exploit this technology for a wide variety of applications from quantifying retinal health by measuring retinal fluorescence lifetimes, to depth imaging through obscurants. 

In fluorescence lifetime imaging and Fluorescence Lifetime Imaging Microscopy (FLIM), biomarkers or fluorophores can be discriminated by their unique, nanosecond scale, decay time facilitating diagnosis of retinal disease at the point of biochemical dysfunction – before loss of sight has occurred. This property of fluorescence lifetime is also invariant to fluorophore concentration and background clutter while also being sensitive to local pH and viscosity. 

For applications in remote sensing, we can measure the time-of-flight experienced by a 100-picosecond long pulse of light to form 3D depth maps, and object detection through obscurants that conventional visible and IR imaging cannot achieve. 

Selected Publications