Study On Physical Characteristics Of A New Type Of Photopolymer Holographic Materials

It is widely believed that photopolymer is a potential recording material owing to its optimum recording characterization. So studying on it is very necessary and significant. The materials researched in the thesis are produced by Technical Institute of Physics and Chemistry Chinese Academy of Sciences.We introduced a new write-read method for the new type of photopolymer with high sensitivity. Utilizing the method, several new materials have been tested and evaluated. The results are given in the forth chapter.The refractive index of the photopolymer was measured with Michelson -interferometer method. We obtained the refractive index of photopolymer samples at different wavelengths and the index change after fully exposure to light.We investigated the scattering noise of the photopolymer in three aspects: the change of the scattering noise with exposure time; the spatial distribution of the scattering noise and the effect of scattering on the image. A modified dynamic model for transmittance of photopolymers under illumination of a coherent beam is proposed, specifying the growth of scattering related to the fabrication parameters of the material. Experiments agree well with the model.A method of measuring the shrinkage of the photopolymer is given. An explicit relation between Bragg shift and the shrinkage of photopolymer samples is presented based on the changes in both the amplitude and direction of the grating vector, caused by lateral shrinkage and thickness shrinkage. By using this method, we experimentally measured the volume shrinkage of the material.The final chapter shows the comprehensive characteristics of the new photopolymers. After two years study, the holographic characteristics of our material were improved very much. Compared with early materials, the parameters of the latest material were enhanced in maximum index modulation, exposure sensitivity and diffraction efficiency.