Optical transmission/fluorescence reaction and features in ultra-thin dye films by scanning near-field optical/atomic force microscopes (SNOM/AFM)

We will illustrate the topographical structure and optical structure of the merocyanine dye LB films obtained by the scanning near-field optical/atomic force microscopy (SNOM/AFM). In the topographic image of the mutual mixed LB film shows more rough surface structure than that of our expectation, and is grained with average size about 50 nm. In the optical transmission and fluorescence image, the elevated area means higher transmission than lower parts. In the continuous measurement on these dyes and the mutual mixed films, the appearance of near-field optical transmission images showed a certain dependence on the kinds of dyes with shift and increase of transmission and the mutual mixing ratios of dyes. These experimental results suggest that there is a certain kind of interaction between these two dyes. This suggests also that the J-aggregate formation and fluorescence change are affected by the domain shape and excitation laser