Record Details


Field	Value

Title	Schlieren interferometric concealed coded security holograms

Creator	Kumar, Raj Aggarwal, A K

Description	429-433 A method has been described to create concealed codes in security holograms. The codes are in the form of pure phase patterns and require an interferometric scheme to convert these invisible phase variations into detectable amplitude/intensity variations. An interferometrically encoded reference beam from the key hologram captures a phase modulated object beam to form the security hologram. In the final reading process, a moiré-like fringe pattern gets generated in the observation plane when the same reference beam illuminates security hologram. This moiré pattern is helpful in verifying the genuineness of the hologram and also facilitates in repositioning of security hologram. In the null mode moiré position, true object wavefront gets reconstructed but the information of concealed codes still remains invisible. Use of schlieren technique is proposed as a simple way to reveal the concealed codes for security hologram authentication. These concealed codes can be used as an anti-counterfeiting feature in embossed security holograms.

Date	2008-12-05T05:58:30Z 2008-12-05T05:58:30Z 2007-05

Type	Article

Identifier	0019-5596 http://hdl.handle.net/123456789/2509

Language	en_US

Relation	G03H

Publisher	CSIR

Source	IJPAP Vol.45(5) [May 2007]

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