为了利用二值空间光调制器实现多灰阶全息存储,将待存储数据页分解成一系列等价二值数据页,并将记录时间分割成与二值数据页对应的一系列递减时间段,每个时间段使用二值空间光调制器加载相应的二值数据页与参考光在存储介质内部干涉记录一系列全息图。从理论上证明了再现所得数据页的灰阶分布与待存储的数据页一致,并从实验上验证了用二值空间光调制器实现四灰阶存储的可行性。多灰阶全息存储提高了每幅数据页的信息量,更加充分地利用了存储介质的动态范围,提高了存储密度与读出数据传输速率。

In order to implement multi-gray-level holographic storage using a binary spatial light modulator,a data page to store is divided into a series of equivalent binary data pages. The recording time is also split into a series of time slices corresponding to the binary data pages. During each time slice,a binary data page is uploaded by the binary spatial light modulator into the object beam which interferes with the reference beam. A series of holograms are recorded in the material. It is proved theoretically that the gray-level distributions of the reconstructed data page are equal to those of the original data page. An experiment of four-gray-level storage is carried out to verify its feasibility. The multi-gray-level storage method can enlarge the capacity of the stored data page. The dynamic range of the material is fully made use of. And the storage density and readout data rate are both improved.