This review presents a reflection-type holographic memory using three-dimensional(3D)speckle-shift multiplexing. First, the schematic of the proposed memory system was described. Then,experimental demonstrations of mu...This review presents a reflection-type holographic memory using three-dimensional(3D)speckle-shift multiplexing. First, the schematic of the proposed memory system was described. Then,experimental demonstrations of multiplexing in plane and along the depth direction were presented. The estimated storage capacity of single layer recording was introduced and the maximum storage capacity was discussed. To increase the storage capacity, the multi-layered recording was described. In the multilayered recording, the storage capacity can be increased by appropriate arrangement of holograms in each layer.展开更多
Holographic data storage system （HDSS） has been a good candidate for a volumetric recording technology, due to their large storage capacities and high transfer rates, and have been researched for tens of years after...Holographic data storage system （HDSS） has been a good candidate for a volumetric recording technology, due to their large storage capacities and high transfer rates, and have been researched for tens of years after the principle of holography was first proposed. However, these systems, called conventional 2-axis holography, still have essential issues for commercialization of products. Collinear HDSS, in which the information and reference beams are modulated co-axially by the same spatial light modulator （SLM）, as a new read/write method for HDSS are very promising. With this unique configuration, the optical pickup can be designed as small as DVDs, and can be placed on one side of the recording media （disc）. In the disc structure, the preformatted reflective layer is used for the focus/tracking servo and reading address information, and a dichroic mirror layer is used for detecting holographic recording information without interfering with the preformatted information. A 2-dimensional digital page data format is used and the shift-multiplexing method is employed to increase recording density. As servo technologies are being introduced to control the objective lens to be maintained precisely to the disc in the recording and reconstructing process, a vibration isolator is no longer necessary. Collinear holography can produce a small, practical HDSS more easily than conventional 2-axis holography. In this paper, we introduced the principle of the collinear holography and its media structure of disc. Some results of experimental and theoretical studies suggest that it is a very effective method. We also discussed some methods to increase the recording density and data transfer rates of collinear holography.展开更多
文摘This review presents a reflection-type holographic memory using three-dimensional(3D)speckle-shift multiplexing. First, the schematic of the proposed memory system was described. Then,experimental demonstrations of multiplexing in plane and along the depth direction were presented. The estimated storage capacity of single layer recording was introduced and the maximum storage capacity was discussed. To increase the storage capacity, the multi-layered recording was described. In the multilayered recording, the storage capacity can be increased by appropriate arrangement of holograms in each layer.
文摘Holographic data storage system （HDSS） has been a good candidate for a volumetric recording technology, due to their large storage capacities and high transfer rates, and have been researched for tens of years after the principle of holography was first proposed. However, these systems, called conventional 2-axis holography, still have essential issues for commercialization of products. Collinear HDSS, in which the information and reference beams are modulated co-axially by the same spatial light modulator （SLM）, as a new read/write method for HDSS are very promising. With this unique configuration, the optical pickup can be designed as small as DVDs, and can be placed on one side of the recording media （disc）. In the disc structure, the preformatted reflective layer is used for the focus/tracking servo and reading address information, and a dichroic mirror layer is used for detecting holographic recording information without interfering with the preformatted information. A 2-dimensional digital page data format is used and the shift-multiplexing method is employed to increase recording density. As servo technologies are being introduced to control the objective lens to be maintained precisely to the disc in the recording and reconstructing process, a vibration isolator is no longer necessary. Collinear holography can produce a small, practical HDSS more easily than conventional 2-axis holography. In this paper, we introduced the principle of the collinear holography and its media structure of disc. Some results of experimental and theoretical studies suggest that it is a very effective method. We also discussed some methods to increase the recording density and data transfer rates of collinear holography.
