Inhomogeneity near-field scanning optical microscopy

Vanden Bout D A, Kerimo J, Higgins D A and Barbara P F 1996 Spatially resolved spectral inhomogeneities in small molecular crystals studied by near-field scanning optical microscopy J. Chem. Phys. 100 11 843-9... 

Near-field scanning optical microscopy was applied to study the effect of a 2D array of silver nanoparticles on the spatial distribution and the magnitude of the fluorescence signal enhancement for a monolayer of Rhodamine 6G (Rh6G) and fluorescently labeled polyelectrolyte PAH-F1TC. The results demonstrate inhomogeneous distribution of the fluorescence signal on the surface. 

Aoki, H., Tanaka, S Ito, S. and Yamamoto, M. (2000) Nanometric inhomogeneity of polymer network investigated by scanning near-field optical microscopy. Macromolecules, 33, 9650-9656. 

Figure 21. Six sequential images of the same sample area of individual carbocyanine dye molecules spread over a polymethylmethacrylate (PMMA) film as recorded by scanning near field optical microscopy. The image dimensions are 2.3 x 2.7-/nn cut out from 4 x 4-fim records of 256 x 256 data points. The excitation polarization was random in (A-D) and linear along y and x, respectively, in ( ) and (F). The emission polarization was measured along y and x in (B) and (C) and not otherwise. Some fluorescence spots are labeled for discussion in the text. The various shapes of the fluorescence peaks (circular spots, rings, arcs, and double arcs) are striking. These shapes can be explained by molecular dipoles being excited by the inhomogeneous electric field at the aperture. (Adopted from [83].)...

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