Optical properties of organic photorefractive polymers for phase retrieval and filtering

New polyphosphazene organic photorefractive materials with carbazole groups were synthesized by diazo-coupling reaction. They were characterized by 1H Nuclear magnetic resonance，infrared spectrum，Ultra-violet-visible，thermogravimetry and differential scanning calorimetry. The result showed that polymers had good heating stability. They started to decompose at 230 ℃ and decomposed completely at 450 ℃. UV-Vis indicated that the broad absorption peak ranging from 360 to 570 nm was derived from the increase in the conjugation length. Hence we can adjust the ratio of diazonium salt in the coupling reaction to control the access content of azo chromophore functional component. The photorefractive effects were investigated without electric field and polarization by two-beam coupling (2BC) and degenerated four-wave mixing(DFWM).The coupling coefficients of polymers P-2 and P-3 are measured to be about 38 cm-1 and 53.6 cm-1 respectively and the diffraction efficiencies of polymers P-2 and P-3 are measured to be about 2.7% and 8.1% respectively.