Paper
8 March 1995 Storage of multivolume holograms using the phase-encoding technique
Theo T. Tschudi, Cornelia Denz, Jan Lembcke, Markus Sedlatschek
Author Affiliations +
Proceedings Volume 2461, ROMOPTO '94: Fourth Conference in Optics; (1995) https://doi.org/10.1117/12.203545
Event: ROMOPTO '94: 4th Conference on Optics, 1994, Bucharest, Romania
Abstract
Reconfigural volume holograms are important for a wide range of multiple data storage applications, including optical interconnection systems, image processing and neural network models. Several techniques for multiplexing to obtain a large number of stored images which can be recalled independently have been developed. But even the most promising of these multiplexing techniques, angular multiplexing using the selectivity of the Bragg-condition, revealed to be limited primarily because of cross-correlation noise. Other problems are not less severe. In this paper we present an alternative approach implementing a phase coding method of the reference beam. Phase encoding has been discussed for interconnecting vector arrays in thin holograms and to perform array interconnections by correlation of a reference beam with a supplementary phase-coded input beam. In contrast to these investigations, we use a reference beam phase coding method in thick volume holographic media, taking thus full advantage of the selectivity of the Bragg-condition in volume storage media. In our experiments, we stored with pure and deterministic orthogonal phase references 64 images into a photorefractive BaTiO3-crystal. For this we developed a special phase modulator on the basis of a liquid crystal display. Good reconstruction with low crosstalk could be observed. Compared to other multiplexing techniques as angular multiplexing, our method allows high storage capacity without alignment problems. Moreover, easy, light efficient as well as immediate image retrieval without any time delay is possible. Experimental setup and results will be presented. We will especially discuss in detail advantages and disadvantages of this coding method compared to others.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Theo T. Tschudi, Cornelia Denz, Jan Lembcke, and Markus Sedlatschek "Storage of multivolume holograms using the phase-encoding technique", Proc. SPIE 2461, ROMOPTO '94: Fourth Conference in Optics, (8 March 1995); https://doi.org/10.1117/12.203545
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KEYWORDS
Multiplexing

Holograms

Volume holography

Computer programming

Data modeling

Data storage

Image processing

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