Fig. 5.

Raman images of the same area on selected fractal and nonfractal surfaces for various excitation laser polarizations where “parallel” is chosen arbitrarily. (A) Raman images of microscope immersion oil on silver films (100 nm thick) with laser power of 9 μW. (B) Raman images of 4-mercaptopyridine adsorbed on the cluster–cluster aggregated films with 0.6-μW excitation power. (C) Raman images of immersion oil on mirror reaction films with 1.9-μW excitation power. The excitation wavelength in each case is 632.8 nm. The size of each image is 5 μm × 5 μm. Note that each image is internally normalized to its maximum so that relative intensities between images cannot be compared. In particular, the hot spots on fractal surfaces have orders of magnitude more Raman scattering than counterparts of similar color on nonfractal surfaces.