THE diffraction limit—a fundamental barrier in light
microscopy—has been broken, paving the way for high-resolution imaging of
live cells, say Stefan Hell and colleagues at the Max Planck Institute for
Biophysical Chemistry in Göttingen, Germany.
The resolution of a fluorescent light microscope depends on the size of the
spot it produces in the material being viewed: the smaller the spot, the better
the resolution. So Hell’s team first created a spot using a green laser. Then,
using a red laser, they “switched off” the fluorescence at the edges, making the
green spot much smaller (Proceedings of the…
