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Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 37, Iss. 35 — Dec. 10, 1998
  • pp: 8181–8186

Optical Encryption System That Uses Phase Conjugation in a Photorefractive Crystal

G. Unnikrishnan, Joby Joseph, and K. Singh  »View Author Affiliations


Applied Optics, Vol. 37, Issue 35, pp. 8181-8186 (1998)
http://dx.doi.org/10.1364/AO.37.008181


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Abstract

We implement an optical encryption system based on double-random phase encoding of the data at the input and the Fourier planes. In our method we decrypt the image by generating a conjugate of the encrypted image through phase conjugation in a photorefractive crystal. The use of phase conjugation results in near-diffraction-limited imaging. Also, the key that is used during encryption can also be used for decrypting the data, thereby alleviating the need for using a conjugate of the key. The effect of a finite space–bandwidth product of the random phase mask on the encryption system’s performance is discussed. A theoretical analysis is given of the sensitivity of the system to misalignment errors of a Fourier plane random phase mask.

© 1998 Optical Society of America

OCIS Codes
(070.1170) Fourier optics and signal processing : Analog optical signal processing
(070.2590) Fourier optics and signal processing : ABCD transforms
(160.5320) Materials : Photorefractive materials
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(190.5040) Nonlinear optics : Phase conjugation
(330.6110) Vision, color, and visual optics : Spatial filtering

Citation
G. Unnikrishnan, Joby Joseph, and K. Singh, "Optical Encryption System That Uses Phase Conjugation in a Photorefractive Crystal," Appl. Opt. 37, 8181-8186 (1998)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-37-35-8181


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References

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