REVERSIBLE SATURABLE OPTICAL FLUORESCENCE TRANSITION (RESOLFT)
Reversible saturable optical fluorescence transitions (RESOLFT) denotes a group of optical microscopy techniques with very high resolution. Using standard far field visible light optics a resolution far below the diffraction limit down to molecular scales can be obtained. STORM is based on collecting a large number of images each containing just a few active isolated fluorophores. Reversible switching between a fluorescent on-state and a dark off-state of a dye is exploited to acquire an imaging sequence where the position of a fluorophore is calculated with a precision typically greater than the diffraction limit. During each cycle, the density of activated molecules is kept low enough that the molecular images of individual fluorophores do not typically overlap.