Photosensitive organic/inorganic azopolymer based nanocomposite materials with enhanced photoinduced birefringence

• Synthesis of novel composite materials by doping ZnO nanoparticles in azopolymers.
• Considerable improvement of the photoresponse in these composite materials.
• 40% increase of the birefringence, reduction of the recording time with 30%.

Different methods have been employed in order to increase the value of the photoinduced anisotropy in azopolymers and to ensure more effective polarization recording. As recently established, doping photopolymers with nanoparticles allows to achieve near 100% net diffraction efficiency in case of conventional holographic recording. For this reason, we have synthesized novel organic/inorganic composite materials by incorporating 50 nm sized ZnO nanoparticles in series of side-chain azopolymers. We obtained a considerable improvement of the photoresponse in these composite materials compared to the non-doped samples – more than 40% increase of the saturated value of the birefringence (up to Δn = 0.08) and also reduction of the recording time with about 30%. We also observed an increase of the photoinduced anisotropy after the exposure has been stopped for one of the investigated polymers. The stability of the photoinduced birefringence in all samples suggests applications of these materials as media for polarization holographic data storage and recording of diffractive optical elements with high efficiency and unique polarization properties.