Multiplexing encryption–decryption via lateral shifting of a random phase mask

✍ Scribed by John Fredy Barrera; Rodrigo Henao; Myrian Tebaldi; Roberto Torroba; Néstor Bolognini

• Book ID: 103871516
• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 271 KB
• Volume: 259
• Category: Article
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2005.09.027

✦ Synopsis

We present an holographic memory optical arrangement based on the successive shifting of a random pure-phase mask to achieve encrypted images multiplexing. The input images are encrypted to a stationary white noise using the usual double random encoding in the Fresnel domain. The encrypted information is imaged in a photorefractive crystal where also a reference beam impinges. In the holographic memory, a BSO crystal is used to provide both a recording medium and a phase conjugate mirror. The combination of these two features supplies at the same time the necessary exact cancellation of the random pure-phase mask as well as allows a real-time decryption process. Successive images are encrypted and position-encoded by speckle patterns arising from the random pure-phase mask in-plane shifting between exposures. We include experimental results to corroborate the multiplexing capability and the read-out fidelity of the proposed arrangement.