Deep Learning Based On Photoinduced Dynamic Effects In Holographic Polymeric Materials (PQ/PMMA)

In recent years,with the development of the information technology industries,holographic storage technology has become an attractive information technology with the advantages of large storage capacity,high storage density,fast transmission speed and etc.The key of holographic storage technology is to seek a type of ideal recording material.Photopolymer material with its high sensitivity,high diffraction efficiency,low cost and simple fabrication has become one of the ideal candidates for holographic storage technology.Especially the PQ/PMMA photopolymer holographic storage material has become a research hotspot with its negligible volume shrinkage effect and large thickness characteristic.The focus of this thesis is to explore the formation mechanism of PQ/PMMA grating in holographic recording process,and further study its optical properties.In order to further investigate the optical properties of optical polymeric materials(PQ/PMMA),according to the detailed fundamental theory of the holographic polymeric materials and its internal photochemical reactions,mechanisms and effects,then apply mathematical and chemical methodology to establish a theoretical model to govern all the associated processes.Optical performance parameters mainly include the diffraction efficiency,sensitivity,and the refractive index modulation which are crucial for the optical polymer materials.According to the Kogelnik's definition of the diffraction efficiency,the diffraction efficiency of the grating is known to be related to the refractive index modulation,which is mainly determined by the concentration conversion from monomer to polymer chains.In this thesis,the change of the concentration of each component and the index of refraction in the process of grating formation are analyzed,and then apply the developed one-dimensional reaction-diffusion model to analyze the exposure intensity,spatial frequency,diffusion rate and other parameters impacts on the optical performances of PQ/PMMA material.Finally,throughout the comparisons between the experimental data and the theoretical data fitting,a series of analyses and discussions is given.Obtained results show that under the given parameter settings,the suitable choices for exposure intensity is 60?80mW/cm2,and for spatial frequency is 1500?1800 lines/mm respectively.