Photorefractive polyvinylcarbazole composite bearing the tricyanopyrrolidene chromophore operating at 830 nm

We report the photorefractive properties of near IR-sensitive polyvinylcarbazole composites containing the tricyanopyrrolidene (TCP) chromophore. New nonlinear optical chromophores bearing the tricyanopyrrolidene (TCP) acceptor were synthesized to improve the optical nonlinearity and the infrared sensitivity via a charge transfer complex. 2-[1-Allyl-3-cyano-4-(4- dibutylamino-phenyl)-5-oxo-1,5-dihydro-pyrrol-2-ylidene]-malononitrile (DBA-TCP) and 2-[3-cyano-4-(4-dibutylaminophenyl)-5-oxo-1-propyl-1,5-dihydro-pyrrol-2- ylidene]-malononitrile (DBP-TCP) had relatively high figures of merit compared to the other conventional chromophores. In the photoionizable poly(9-vinylcarbazole) (PVK), the tricyanopyrrolidene (TCP) chromophore was doped in the presence of (2,4,7-trinitro-fluorenylidene)malononitrile (TNFM), A two-beam coupling experiment at 830 nm provided clear evidence for asymmetric energy transfer phenomena and for a high gain coefficient.