Self-Organized Arrays of Sub-Micrometer Particle of Organic Dye for Near-Field Optical Study
Yasuyuki Ido, Akihiro Tomioka, Yasuaki Itakura and Tooru Motokubota
Organic dye particles of micrometer and sub-micrometer size formed as precipitates on a glass surface when the organic solvent evaporated from a thin film of specimen solution at a precisely controlled evaporation rate showed a typical one- or two-dimensional registration. We identified the near-field fluorescence from separated particles within these self-organized particle arrays. Some of the particles did show near-field-excited near-field fluorescence, whereas the majority of the particles did not show fluorescence even in the first photo-excitation experiment. The dye molecules may be in an optically inactive state due to oxidation by ambient oxygen, or they may be tightly coupled to the glass substrate to which emitted photons were leaked and were not coupled to the probe.