The waves always 'spread' to some extent into the area beyond the gap. This is diffraction - the spreading out of waves when they go through a gap, or past the edge of a barrier. The extent of the ...

They explain how two opposing lenses, combined with the switching (on and off) of fluorescence between adjacent markers, can overcome the diffraction barrier. Although the examples given are ...

or sea waves entering a narrow harbor. Electron diffraction was revolutionary not just for fundamental physics, but led to the development of cutting-edge technology such as the electron microscope.