title: Geometrical phase image encryption obtained with space-variant subwavelength gratings.
abstract: An optical encryption method based on a geometrical phase produced by space-variant polarization manipulation is presented. The decrypted picture is retrieved either by a polarization measurement of the beam emerging from the encrypted element or by a single intensity measurement of the beam transmitted through the encrypted element followed by an optical key element. Both elements are realized by use of computer-generated space-variant subwavelength dielectric gratings. Theoretical analyses of the optical concept are presented along with experimental results.
authors.affiliation: Optical Engineering Laboratory, Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Biener
authors.forename: Avi
authors.initials: A
authors.lastname: Niv
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kleiner
authors.forename: Erez
authors.initials: E
authors.lastname: Hasman