Local Morphology and Sub-Wavelength Region Spectroscopy of Molecular J-Aggregates Onset of Exciton-Polariton States in Individual Aggregate Fibers

We present results on reflection microscopy and local spectroscopy of J-aggregates of pseudoisocyanine dyes in a thin film polymer matrix. Local reflectance spectra reveal a wide distribution of optical properties within different locations of one sample. The spectral lineshapes and absolute reflectivities are suggested to originate from varying strength of exciton-photon interaction. Polarization dependence measurements of local reflectivities at different wavelengths provide orientations of the excitonic transition dipole moments with respect to the orientation of the aggregate fibers.