Novel photorefractive (PR) hybrid composites have been developed, based on a functional polymer poly(N-vinylcarbazole)
(PVK) sensitized with nanocrystalline lithium niobate (LiNbO3). A comparison study between traditional
organic PR material sensitized with 2,4,7-trinitro-9-fluorenone (TNF) and novel composites mentioned above was made with respect to their photorefractive behavior at 633 nm. The steady-state and the kinetics of the photorefractive gratings in the materials under study were investigated in degenerate four-wave mixing (DFWM) and two-beam-coupling (TBC) experiments in a tilted geometry. It was shown that photorefractive properties of new composites are strongly influenced by the concentration of nanocrystals. The effect of co-sensitization, by the traditional 2,4,7-trinitrofluorenone and the LiNbO3 nano-crystals, was discovered. This yields materials with improved PR performance compared to that of the standard PR polymer material sensitized by TNF only.