SUPERRESOLUTION FLUORESCENCE IMAGING OF SINGLE DYE MOLECULES IN THIN POLYMER-FILMS

We report on the imaging of single dye molecules in thin polymer films under ambient conditions by means of scanning near-field optical micr oscopy. The long-term mechanical stability and high detection efficien cy of our instrument allow the imaging of single dye molecules over se veral hours with a high signal-to-noise ratio. The local excitation by the near-field tip, the low excitation power and the fact that the dy e molecules are embedded in the three dimensional polymer structure dr astically reduce photodestruction as compared with conventional micros copy. The observation of many molecules in the same film allows to pro be them under identical experimental conditions and to statistically a nalyze their global behavior. We find that the molecules diffuse and r otate within the polymer matrix. The single dye molecules act as nanom eter-sized probes and reflect the local structure of the polymer. (C) 1997 American Vacuum Society.