Miniaturization Of Holographic Storage System: Design And Demonstration

Volume holographic storage is the most potential information storage technology, owing to the high storage capacity and fast data rate. It has a wide prospect in such fields as information processing, aviation and spaceflight, multimedia and large database. However, the system generally used for volume holographic storage is too large, and can only be used on vibration-isolated holographic table. Moreover, it is hard to be adjusted. All these will limit the practicability of holographic storage. To make the holographic storage more practical and even commercial, it must be miniaturized firstly, and integrates in a small place. In this thesis, the design, test and verification of the minitype holographic storage has been described in detail based on the theory of volume holographic storage, especially, on the angular-selectivity. To the generally used photorefractive crystal, band transport model about the stimulation and transportation of charge carriers has been described in this paper. One problem of the maniaturazation is to find a miniature laser. Through wide investigation, we selected a sort of pocket solid laser with small volume and high output power( pumped by laser diode). To verify its potential for holographic storage, we studied its characteristic such as the coherence, frequency- stability and power-stability. We conducted holographic experiments with this laser and get a satisfactory result. From the results, we concluded that the pocked solid laser is suitable for holographic storage. At the same time, the material characteristic is studied thoroughly. The single-doped LiNbO3 crystal (Fe-doped) has good characteristic at 5 l4nm wavelength of Argon-Ion, but is not sensitive to red light. To find out the material, which is sensitive to 51 4nm wavelength and red light, we tested double-doped LiNbO3 (Ce:Fe:LiNbO3). The comparison of single-doped and double-doped LiNbO3 and the results at green light are given in this paper. It shows that Ce and Fe double-doped LiNbO3 is more suitable for holographic storageat both red and green light. Moreover, we designed a miniature holographic storage system after comparing several different holographic systems. All the storage-method, light-addressing scheme, the selection schedule of optic components are included. The storage capacity, exposure time and the possibility of actual usage of this system are also analyzed. Using this system, we conducted multiplexing image storage and got satisfactory results, which demonstrated the performance of the system. Mechanical design was given after the optic design. All parts was fixed in together to be a demonstrating system, which was convenient for transfer, regulation and further study. Finally, we concluded the system design and discussed the direction of future work.