Photorefractive polymer composites based on nanosized nonlinear optical chromophores

Photorefractive (PR) polymer composites based on polymers with a high glass transition temperature in which the random distribution of a photosensitizer and a nonlinear optical chromophore as dopants is “frozen” were designed. In the case of the random distribution of chromophores, only the third-order electric susceptibility has a nonzero value. Therefore, nanosized structures having high third-order polarizability due to an extended conjugated-bond system (or cooperative electronic excitation) were used as nonlinear chromophores. Good PR characteristics are displayed by polymeric composites containing nanosized structures, such as cyanine dye J aggregates, supramolecular assemblies of ruthenium(II) complexes, and single-wall carbon nanotubes. The use of extended nanosized chromophores as simultaneous spectral sensitizers allowed polymer composites with PR sensitivity in the near IR region at 1064 and 1550 nm to be designed.