For many centuries improving the resolution of light microscopy meant perfecting lenses and other optical elements, a strategy whose limits became evident with the discovery of the diffraction barrier in 1873. From there onwards, it was well accepted that the resolution of any light-focusing microscope is limited by the wavelength of light in use. At the turn of this century, the diffraction barri
er was radically overcome, and it became clear that lens-based fluorescence microscopes can resolve features down to the molecular scale. At its most fundamental level, this breakthrough in resolution is based on the fact that tiny features in the sample are no longer discerned by the focusing of light. Rather the feature molecules or molecular tags are prompted to briefly assume two different states (e.g. fluorescence on/off) so that they become distinguishable when illuminated by the same diffraction pattern. Thus, in modern superresolution microscopy – in short, “nanoscopy” – fluorescent molecular tags have to fulfill a double role. Not only do they have to highlight the features of interest, but they also have to provide the (pair of) states required for separation. Therefore, it is the symbiosis of molecular tags and optical design that makes the microscopes of today sharp and bright. This conference brings together experts in fluorescence and labeling with those designing and applying new concepts of far-field optical nanoscopy. It is a sequel to the very successful first event held in 2014.
