Near-field fluorescence imaging of single molecules with a resolution in the range of 10 nm

We demonstrate fluorescence imaging of single molecules, by near-field scanning optical microscopy (NSOM), using the illumination-collection mode of operation, with an aperture probe. Fluorescence images of single dye molecules were obtained with a spatial resolution of 15 nm, which is smaller than the diameter of the aperture (20 nm) of the probe employed. Such super-resolution may be attributable to non-radiative energy transfer from the molecules to the coated metal of the probe since the resolution obtained in the case of conventional NSOM is limited to 30–50 nm due to penetration of light into the metal.