Effect of the chromophore donor group and ferrocene doping on the dynamic range, gain, and phase shift in photorefractive polymers

We have studied the photorefractive performance of poly(N-vinylcarbazole)-based composites doped with various concentrations of two structurally related dipolar chromophores, at 780 nm. The two chromophores had different electron donor groups, N,N-diethylamine and julolidine, respectively. Complete internal diffraction and gain coefficients > 130 cm(-1) were obtained for polymers doped with these chromophores. The polymers prepared with the chromophore having the strongest electron donor group, the julolidine group, had the largest dynamic range, but proved to be slower and had a smaller photorefractive phase shift. (C) 2000 American Institute of Physics. [S0021-9606(00)70137-1].