Three dimensional super-localization microscopy
Super-resolution fluorescence microscopy has revolutionised the field of cellular imaging in recent years. Methods based on sequential localisation of point emitters (e.g. PALM, STORM) enable imaging and spatial tracking at ~10-40 nm resolution, using visible light. Moreover, three dimensional (3D) tracking and imaging is made possible by various techniques, prominent among them being point-spread-function (PSF) engineering. The PSF of a microscope, namely, the shape that a point source creates in the image plane, can be modified to encode the depth (z position) of the source. This is achieved by shaping the wavefront of the light emitted from the sample, using a phase mask in the pupil (Fourier) plane of the microscope.
In this talk, I will describe how our search for the optimal PSF for 3D localization, using tools from information theory, led to the development of microscopy systems with unprecedented capabilities in terms of depth of field and spectral discrimination. Such methods enable fast, precise, non-destructive localization in thick samples and in multicolor; we have applied them to super-resolution imaging, tracking biomolecules in living cells and microfluidic flow profiling. Super localization microscopy holds great promise as a uniquely powerful tool for future measurements of nano-scale dynamics in living systems.