A technique has been developed to obtain three-dimensional structural information on a length scale well below the Rayleigh length with conventional far-field optics. By spectrally selecting a single molecule with high-resolution laser spectroscopy and using a CCD camera to register the spatial distribution of the emitted photons in three dimensions, one can determine the position of a molecule with unprecedented accuracy. One can resolve details in the specimen with sub-diffraction-limited resolution in three dimensions by applying this procedure to as many molecules as are present in the same diffraction-limited volume and obtaining their mutual positions. The feasibility of this technique is demonstrated for the system of pentacene in <i>p</i>-terphenyl at cryogenic temperatures for which molecules were localized with an accuracy of better than 40 nm in the lateral and 100 nm in the axial directions.
© 1999 Optical Society of America
A. M. van Oijen, J. Köhler, J. Schmidt, M. Müller, and G. J. Brakenhoff, "Far-field fluorescence microscopy beyond the diffraction limit," J. Opt. Soc. Am. A 16, 909-915 (1999)