Space-variant polarization scrambling for image encryption obtained with subwavelength gratings

We present an optical encryption method based on geometrical phase, which is originated from polarization manipulation. The decrypted picture is retrieved by measuring the polarization of the beam emerging from the encrypted element. The encrypted element is achieved by using a computer-generated space-variant subwavelength dielectric grating. Theoretical analyses of the optical concept by use of Jones and Mueller formalisms, as well as experimental results including full optical decryption process are introduced. Digital implementation and the possibility of using watermarking are also discussed.

[1]  G. Unnikrishnan,et al.  A polarization encoded optical encryption system using ferroelectric spatial light modulator , 2000 .

[2]  J. Glückstad,et al.  A phase-based optical encryption system with polarisation encoding , 2000 .

[3]  B Javidi,et al.  Optical image encryption based on input plane and Fourier plane random encoding. , 1995, Optics letters.

[4]  Bahram Javidi,et al.  Fully phase encrypted image processor , 1999 .

[5]  Erez Hasman,et al.  Geometrical phase image encryption obtained with space-variant subwavelength gratings. , 2005, Optics letters.

[6]  Soo-Joong Kim,et al.  Interferometric phase-only optical encryption system that uses a reference wave , 2003 .

[7]  Osamu Matoba,et al.  Secure holographic memory by double-random polarization encryption. , 2004, Applied optics.

[8]  O Matoba,et al.  Secure optical memory system with polarization encryption. , 2001, Applied optics.

[9]  G. Unnikrishnan,et al.  Optical encryption by double-random phase encoding in the fractional Fourier domain. , 2000, Optics letters.

[10]  Kehar Singh,et al.  Double random fractional Fourier domain encoding for optical security , 2000 .

[11]  M. Berry.  Quantal phase factors accompanying adiabatic changes , 1984, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[12]  P C Mogensen,et al.  Phase-only optical encryption. , 2000, Optics letters.

[13]  Bahram Javidi,et al.  Polarization encoding for optical security systems , 2000 .

[14]  B Javidi,et al.  Optical security and encryption with totally incoherent light. , 2001, Optics letters.

[15]  James D. Brasher,et al.  Optical recognition of phase-encrypted biometrics , 1998 .

[16]  Erez Hasman,et al.  Polarization dependent focusing lens by use of quantized Pancharatnam–Berry phase diffractive optics , 2003 .

[17]  Bahram Javidi,et al.  Optical encryption using a joint transform correlator architecture , 2000 .

[18]  Jingjuan Zhang,et al.  A lensless optical security system based on computer-generated phase only masks , 2004 .

[19]  B Javidi,et al.  Optoelectronic information encryption with phase-shifting interferometry. , 2000, Applied optics.

[20]  Chau-Jern Cheng,et al.  Optical image encryption based on polarization encoding by liquid crystal spatial light modulators , 2004 .

[21]  Erez Hasman,et al.  Propagation-invariant vectorial Bessel beams obtained by use of quantized Pancharatnam-Berry phase optical elements. , 2004, Optics letters.