Since super-resolution microscopy techniques revolutionized the concept of light microscopy by overcoming the physical diffraction limit, STED
microscopy and other super-resolution techniques have aroused considerable interest. The diffraction limit imposes no more constraints on resolution. New microscopes with ever-decreasing resolution limits are being developed, for instance by the inventor of STED
microscopy, Prof. Stefan Hell, now director at the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany.