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Proceedings Paper

Polarization holographic data storage using azobenzene polyester as storage material
Author(s): Emoeke Loerincz; Gabor Szarvas; Pal Koppa; Ferenc Ujhelyi; Gabor Erdei; Attila Sueto; Peter Varhegyi; Sz. Sajti; A. Kerekes; T. Ujvari; P. S. Ramanujam
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Paper Abstract

Polarization holographic read/write and read only demonstrator systems have been developed using ~2 µm thick azobenzene polyester on a card form media. The thin-film holographic system has practical advantages, e.g. high diffraction efficiency, no cross talk between the holograms, reading in reflection mode, no hardware servo, different wavelengths for writing and reading (non-volatile storage), data encryption possibility, no problem with material shrinkage, etc. The candidate azobenzene polyester has good thermal, room temperature and ambient light stability and good optical properties for the purpose of thin film application. Using thin-film holography the possibilities of multiplexing are limited, however, raw data density as high as 2.77 bit/µm2 has been achieved in an optimized Fourier holographic system using high numerical aperture (NA³ 0.74) objective in a 8f arrangement with sparse code modulation and Fourier-filtering at 532 nm. High density polarization holographic demonstrator systems have been developed using ~2μm thick azobenzene polyesters on reflective card form media. FFT computer simulation of the system including saturation model of the material allows optimization of system components including data density and capacity. A raw density as high as 2.77 bit/μm2 has been achieved without multiplexing in a compact, portable read/write sytem at 532 nm allowing more than 1000 readout without data loss. A separate read only system working at 635 nm realizes non-volatile readout and allows card exchange at a data density of 1.3 bit/μm2. Security level of the presents holographic optical card systems can be further increased by using phase encoded reference beam. Advantageous applications of the proposed encrypted holographic card system are also outlined.

Paper Details

Date Published: 14 July 2003
PDF: 11 pages
Proc. SPIE 4991, Organic Photonic Materials and Devices V, (14 July 2003); doi: 10.1117/12.479454
Show Author Affiliations
Emoeke Loerincz, Budapest Univ. of Technology and Economics (Hungary)
Gabor Szarvas, Optilink Hungary, Ltd. (Hungary)
Pal Koppa, Budapest Univ. of Technology and Economics (Hungary)
Ferenc Ujhelyi, Budapest Univ. of Technology and Economics (Hungary)
Gabor Erdei, Optilink Hungary, Ltd. (Hungary)
Attila Sueto, Optilink Hungary, Ltd. (Hungary)
Peter Varhegyi, Budapest Univ. of Technology and Economics (Hungary)
Sz. Sajti, Budapest Univ. of Technology and Economics (Hungary)
A. Kerekes, Budapest Univ. of Technology and Economics (Hungary)
T. Ujvari, Budapest Univ. of Technology and Economics (Hungary)
P. S. Ramanujam, Risoe National Lab. (Denmark)


Published in SPIE Proceedings Vol. 4991:
Organic Photonic Materials and Devices V
James G. Grote; Toshikuni Kaino, Editor(s)

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