Near-field fluorescence imaging and simultaneous observation of surface potentials

We present a new detection method to measure simultaneously surface potenti al and fluorescence intensity distributions using a combined scanning near- field optical microscope-atomic force microscope (SNOM-AFM). A surface pote ntial image of phospholipid monolayers was obtained in non-contact mode usi ng the SNOM-AFM with a thin-step etched optical fibre probe. For applying t his technique, a phospholipid of dipalmitoylphosphatidylethanolamine labell ed at the head with a nitrobenzoxadiazole group was used as a fluorescent a nd single component Langmuir-Blodgett film. It is well known that aggregati on of the lipid molecules and their fluorescence intensities are Very sensi tive to its environmental conditions such as humidity and temperature. We d emonstrated for the first time the near-field optical imaging and simultane ous observation of surface potentials with Maxwell stress microscopy.