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Proceedings Paper

Polarization-sensitive multilayer diffractive structures for document security
Author(s): Ivo Aubrecht
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Paper Abstract

Multi-layer diffraction structures with characteristic behavior in monochromatic and white light for the TM polarization that does not occur for the TE polarization are under study. They are composed of a thin film of silver, or the one with thin-film dielectric coatings over and/or under the film, and a pair of enclosing dielectric sheets. A periodic surface relief corrugates boundaries between neighboring layers. The structures are investigated in the transmission mode under various conditions of illumination by measuring the zero-order diffraction efficiency. Refractive indices of the enclosing sheets, of the dielectric coatings, and values of thickness of the latter are critical for high sensitivity to polarization. If such a structure is realized as a foil made of several layers, taking into account also a transparent adhesive fixing the foil to a substrate, the structure may become a promising device for protection of documents against counterfeiting. Theoretical analyses and experimental investigations of laboratory models and realized foil devices are presented.

Paper Details

Date Published: 19 May 2009
PDF: 7 pages
Proc. SPIE 7358, Holography: Advances and Modern Trends, 73580E (19 May 2009); doi: 10.1117/12.820341
Show Author Affiliations
Ivo Aubrecht, Police presidium CR (Czech Republic)

Published in SPIE Proceedings Vol. 7358:
Holography: Advances and Modern Trends
Miroslav Miler; Miroslav Hrabovský, Editor(s)

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