Gao Q, Kostuk R
Appl Opt. 1997 Jul 10;36(20):4853-61. doi: 10.1364/ao.36.004853.
Various effects associated with using a random phase mask in holographic data storage are analyzed. It is shown that the nonlinear nature of recording a phase hologram coupled with the highly nonuniform profile of the object beam is the major source of interpixel cross talk. It is also shown that, although the nonlinear effects are reduced by an increase in the reference-to-object beam ratio, the scattering noise is increased. Thus an optimal beam ratio must be used to maximize the signal-to-noise ratio. It is demonstrated as well that the interpixel interference noise can be suppressed effectively by use of a multilevel pseudorandom phase mask, which also significantly reduces the nonlinear noise. These findings are supported by experimental results that show the signal-to-noise ratio and efficiency are improved significantly by use of a six-level pseudorandom phase mask.
分析了全息数据存储中使用随机相位掩模所产生的各种效应。结果表明，相位全息图记录的非线性特性与物光束的高度非均匀分布相结合，是像素间串扰的主要来源。还表明，尽管通过增加参考光束与物光束的比率可以降低非线性效应，但散射噪声会增加。因此，必须使用最佳光束比率来最大化信噪比。还证明了使用多级伪随机相位掩模可以有效抑制像素间干涉噪声，这也显著降低了非线性噪声。这些发现得到了实验结果的支持，实验结果表明使用六级伪随机相位掩模可显著提高信噪比和效率。
