STARK-EFFECT IN HOLE-BURNING SPECTRA OF DYE-DOPED LANGMUIR-BLODGETT-FILMS

The hole-burning method was applied to Langmuir Blodgett multilayer films doped with low concentrations of an amphiphilic cyanine dye. The Stark effect on a narrow spectral hole leads to a linear-in-field broadening, and for alternate multilayers to a small linear hole shift. By comparing the broadening and the shift with the broadening for bulk systems, the angular distribution of the short chromophore axis was deduced. The chromophore was found to lie flat on the film surface, with larger disorder for the short than for the long axis. The very small shift shows that the chromophore orientation hardly depends on the direction in which the dye's chains are pointing.