Holographic memory with correlator based readout

The investigation of an inverted hybrid digital/optical VanderLugt type correlator based on a holographic memory is reported in this paper. A set of reference templates is stored in a photorefractive crystal (PRC) by angular hologram multiplexing. In the filter plane, a phase-modulating liquid cryst...

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Bibliographic Details
Published inIEEE journal of selected topics in quantum electronics Vol. 4; no. 5; pp. 849 - 855
Main Authors Duelli, M., Pourzand, A.R., Collings, N., Dandliker, R.
Format Journal Article
LanguageEnglish
Published IEEE 01.09.1998
Subjects
Correlators
Holographic optical components
Holography
Liquid crystal devices
Liquid crystals
Optical filters
Optical sensors
Partial response channels
Photorefractive materials
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Summary:The investigation of an inverted hybrid digital/optical VanderLugt type correlator based on a holographic memory is reported in this paper. A set of reference templates is stored in a photorefractive crystal (PRC) by angular hologram multiplexing. In the filter plane, a phase-modulating liquid crystal television (LCTV) serves as a phase-only input device. During the recognition process, which is based on the pure phase correlation, the reference templates are correlated sequentially with the input object. This correlator shows high sensitivity to object rotation, sharp correlation peaks, high light efficiency, and is fully shift-invariant in spite of the PRC thickness. The influences of the LCTV on the performance of the system are discussed and experimental results are shown.
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ISSN:1077-260X
1558-4542
DOI:10.1109/2944.735771