Enderlein, J.
Breaking the diffraction limit with dynamic saturation optical microscopy. Applied Physics Letters 87: 094105-3 (2005).

A scheme of fluorescence microscopy is proposed allowing the breaking of the diffraction limit of optical microscopy by a factor of four to five. It relies on fast temporal measurements of the fluorescence decay after sudden switch-on of the light excitation. The observed temporal dynamics of the fluorescence signal can be converted into information about the spatial distribution of fluorophores within the exciting laser focus. The proposed scheme is technically simple, allows resolution enhancement in three dimensions, and will be robust with respect to small optical aberrations as caused by refractive index variations in real samples.