SPATIAL MULTIPLEXING DEVICE FOR HOLOGRAPHIC MEMORY AND VOLUME HOLOGRAPHIC DIGITAL DATA STORAGE SYSTEM THEREWITH

摘要

The present invention relates to a volume holographic digital data storage system having a backup function, wherein the object light modulated from the spatial light modulator (30) during data recording is applied to the data storage area (61) of the optical refraction crystal (60) as a storage material. It has a structure that transmits and enters the data backup area 65, and the reference light is divided into two by the beam splitter 66, one of which opens the first electronic shutter 70 and the data via the AOD 64. Incident on the storage area 61, the other opens the second electronic shutter 80, enters the data backup area 65 via the AOD 29, and interferes with object light in each area. Record the data. The interference fringes of the object light and the reference light incident and recorded in the optical refraction crystal 60 close the second electronic shutter 80 provided on the optical path of the backup area during normal reproduction, and the first electronic shutter 70 is opened. When the reference light is irradiated at a predetermined angle, the image is restored to the checkered pattern and the image obtained by reading the restored pattern is reflected on the solid state image pickup device 50. When the data stored in the data storage area 61 is damaged by an external shock, the first electronic shutter 70 is closed and the second electronic shutter 80 is opened to irradiate the reference light at a predetermined angle. An interference occurs between the interference pattern recorded in the backup area 65 and the reference light, and data is recovered by reproducing it.;According to the present invention, the reference light is divided into two, and the two reference lights are incident on the storage material by performing angle modulation for angle overlap using the first and second electronic shutters and the AOM, so that the object light passes through the storage material. The recording structure forms two storage areas in the storage material and interferes with each of the reference beams by opening and closing the electronic shutter in each storage area. Therefore, when an error occurs during data reproduction, the automatically backed up data can be used. As a result, the reliability of data storage of the system can be improved.