Hannover 2010 – wissenschaftliches Programm

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SYDI: Symposium Diffractive Imaging

SYDI 1: Imaging of biological systems

SYDI 1.3: Hauptvortrag

Freitag, 12. März 2010, 11:30–12:00, E 415

Far-Field Optical Nanoscopy by Optical Switching — •Andreas Schönle and Stefan Hell — Dept. for NanoBiophotonics, MPI f. biophysical Chemistry, Göttingen, Germany

In 1873 Ernst Abbe recognized that the resolution of every far-field microscope is fundamentally limited by diffraction and this barrier is indeed an unalterable fact for purely optical imaging. For more than a century it was thus naturally assumed that imaging systems operating with visible light will never be able to resolve features smaller than about 250nm. However, recent advances in optical microscopy have radically overcome this limit and resolutions of better than 10nm have been demonstrated. This groundbreaking development is based on the simple but powerful insight that the light-dye interaction rather than the propagation of waves have to be put at the core of the image formation process: The ability to transiently confine adjacent molecules to different states allows the time-sequential recording of spatial features thus eluding the limitations of diffraction. In 1994, the invention of stimulated emission depletion (STED) microscopy demonstrated the feasibility of this approach and several other more or less related diffraction-unlimited far-field optical approaches were successfully implemented since then. All these techniques switch molecules between states in order to record them sequentially in time, either by addressing molecule ensembles inside sub diffraction sized volumes or by stochastically turning on isolated single markers. The resulting resolution is then no longer fundamentally limited by diffraction and can be pushed to the macromolecular scale.