Interferometry based security hologram readable with an encoded key hologram

Aggarwal, A.K. and Kaura, S.K. and Sharma, A.K. and Chhachhia, D.P. (2004) Interferometry based security hologram readable with an encoded key hologram. Indian Journal of Pure & Applied Physics, 42 (11). pp. 816-819. ISSN 0019-5596

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Official URL: http://nopr.niscair.res.in/handle/123456789/9644

Abstract

A simple and cost-effective method for making security holograms has been presented, which incorporates holographic interferometry as verification feature in addition to spatially separated sharp focus spots. When the security hologram is illuminated with decoding reconstructing beam generated from an encoded key hologram, two spatially separated sharp focus spots emerge at the predefined positions and can be read through a photoelectric detector array. In addition, these focused spots upon divergence in longitudinal direction further generate specific kind of interferometric fringe patterns of random profile contained in them, which are suitable for further visual inspection. These machine-readable and visual verifiable features can be used for better counterfeit-resistant security codes in embossed holograms. Recording schemes for the formation of such security holograms and typical experimental results have been presented

Item Type: Article
Uncontrolled Keywords: Security holograms; Holograms; Optical security
Subjects: CSIO > Optics
Depositing User: Ms. Narinder Kaur
Date Deposited: 05 Mar 2012 12:12
Last Modified: 05 Mar 2012 12:12
URI: http://csioir.csio.res.in/id/eprint/55

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