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Optical Engineering

Security holograms using an encoded reference wave
Author(s): Songcan Lai
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Paper Abstract

A new kind of security hologram using an encoded reference wave is presented. The hologram is produced with the interference of an encoded reference wave and a convergent object wave. The encoded reference wave is formed from a plane wave that has passed through a random phase plate. When the hologram is illuminated with a duplicate of the reference beam, a verification pattern (a bright spot) is produced in the output plane. Only if the random phase plate matches the hologram, does sharp focus emerge. Because the verification pattern is simply a spot peak rather than an image pattern, this kind of security hologram is suitable for machine inspection. Therefore, it can be used for better counterfeit-resistant security codes in the form of embossed easy-to-copy holograms. Initial experimental results are given.

Paper Details

Date Published: 1 September 1996
PDF: 3 pages
Opt. Eng. 35(9) doi: 10.1117/1.600850
Published in: Optical Engineering Volume 35, Issue 9
Show Author Affiliations
Songcan Lai, Zhengzhou Institute of Technology (Germany)

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