1) Eric Betzig, Stefan W. Hell and William E. Moerner were awarded the 2014 Nobel Prize in Chemistry for developing super-resolved fluorescence microscopy techniques that allow visualization of structures smaller than the diffraction limit of light.
2) Stefan Hell developed stimulated emission depletion (STED) microscopy, which uses a scanning "nanoscopic flashlight" to achieve resolutions better than 0.2 micrometers.
3) William E. Moerner was the first to detect fluorescence from a single molecule, opening up the field of single-molecule microscopy.