【作者】 宋伟；

【导师】 陶世荃；

【作者基本信息】 北京工业大学 ， 光学， 2010， 硕士

【摘要】 信息社会,传统数字数据处理和存储设备的性能趋近于理论极限,迫切需要新的存储手段应对数据处理的需求,三维体全息存储技术应运而生。与此同时,光致聚合物的深入研究为全息存储创造了必要的物质条件,而实用的全息存储方式是数字数据全息存储。本论文在已有的理论及研究成果基础上在光致聚合物材料里进行高质量高密度的数字数据全息存储方案研究。本文首先介绍了体全息存储的基本原理,总结了全息存储的各种复用方法以及存储图像质量的评价方法。随后讨论了实现高密度高质量全息存储的途径,对各种复用方案进行了讨论。作为研究工作的一部分,我们与中国科学院理化技术研究所合作,定量测量了其提供的双单体体系材料的信噪比损失(LSNR),研究光了致聚合物材料的噪声性能。各种复用方案利用了各种不同类型的参考光,我们提出参考光的波面质量对全息存储的质量会带来重要的影响,有必要进行各种类型参考光对全息记录再现图像质量影响的讨论。我们根据全息记录和读出的物理模型,利用MATLAB软件模拟实际傅里叶变换全息图的记录和再现,分析参考光(主要是平面波、高斯光束参考光、散斑参考光和散斑成像参考光)对再现图像质量的影响并进行了初步的验证实验,实验结果表明平面波参考光全息读出图像质量非常好,但是对于散斑参考光,其再现图像质量明显变差。尽管散斑成像作为参考光的读出图像质量稍好一些,但是依然造成图像质量下降。因此,为了实现有效的数据存储位密度,在使用随机位相复用技术提高存储密度的同时,应当采取措施改善再现像的质量,考虑优化参考光的途径。鉴于随机位相参考光的数值模拟结果和初步试验结果,而其它参考光如平面波参考光、高斯光束参考光又难以达到较高的存储密度,我们将目光转向确定性位相编码调制参考光——正交位相编码调制参考光。我们用数值模拟方法研究正交位相编码参考光位移复用方案,模拟结果表明其存储密度可以达到120bits/μm2且读出图像质量非常好。在以后的工作中我们会选择这个存储方案进行实现高质量高密度数字数据全息存储的研究。更多还原

【Abstract】 In the modern information society, the requirements for high storage density and high data transfer rates are constantly rising. But the traditional technology for storage and data processing device has developed to its limit and new way to store information is needed. Then, a new technology, volume holographic storage, is developed. The development of photopolymer material offers storage material for this technology, and the digital data storage is the way to make it true. In this thesis, the purpose is to study a design scheme for realizing digital data holographic storage with high quality and density.Firstly, the principles of volume holographic storage are introduced, various methods of multiplex technology for storage are summarized and the way to evaluation the quality of storage is also discussed. As a part of my research work, the thesis has accomplished the measurement of different series of photopolymers which are provided by Technical Institute of Physics and Chemistry of Chinese Academy of Science. In those measurements, the scattering noise of photopolymer was deeply investigated by means of Loss of Signal-to-Noise Ratio (LSNR).Based on those background knowledge, the thesis study the way to realize the high density and quality in holographic data storage. Different multiplex methods often mean making use of different kinds of reference beams. So it is necessary to study the influence of reference beams (general plane beam, Gaussian beam, speckle beam, and speckle imaging reference beam) on the quality of holographic storage. The results of the research show that with plane reference, the quality of reconstructed images are very good and with Gaussian beam the noise of the reconstructed images is restrained but the boundary information is also weakened; however, with speckle reference, the quality of the images is not good; although with the speckle imaging reference, the situation is a little better. So, it is necessary to improve the quality of the reconstructed images when the random-phase multiplexing technology is to be used for high density storage. And in order to implement high-density holographic storage with high reconstruct quality, the reference beam must be optimized.According to the discussion above, we go on to study the deterministic phase-modulated multiplex method, the orthogonal phase-coding. Also by numerical simulation we study the new optical setup design of shift-multiplexing method with reference beam which is modulated by orthogonal phase-coding. The results show the storage quality is good and it is calculated that the storage density can be about 120bits/ m2. We will go ahead doing research on holographic storage with this design to realize the high density and high quality digital data holographic storage.更多还原