Accession Number : ADP006798
Title : Multiple Grating Optical Processing in Barium Titanate,
Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO)
Personal Author(s) : Boothroyd, S. A. ; Beckwith, P. H. ; Chan, L. ; Chrostowski, J.
Report Date : 22 MAY 1992
Pagination or Media Count : 4
Abstract : Nonlinear optical image subtraction and Boolean XOR operations have been demonstrated in Michelson interferometers with phase conjugate mirrors. The two interferometer arms each contain a light modulating transmission or reflection element which must be carefully registered and imaged at the interferometer output. Destructive interference between the output images of the two arms arises because one image undergoes a extra pi phase change on reflection from a dielectric interface. Image subtraction has also been achieved in photorefractives via double exposure holography where two gratings are formed by displacing the reference beam in phase by pi. A pi phase shift on one of the writing beams in four wave mixing has also been used to selectively erase volume holograms in photorefractive media. We describe a new approach using phase conjugation in barium titanate by which image subtraction, the logic XOR, and also the logic OR operation are achieved. Our simple arrangement uses only two mutually coherent input beams for four-wave mixing phase conjugation. Unlike phase conjugate Michelson interferometry the two input images arise from the same modulation element and are automatically registered.
Descriptors : *BARIUM TITANATES, *INTERFEROMETERS, *OPTICAL IMAGES, *OPTICAL PROCESSING, BARIUM, DIELECTRICS, HOLOGRAMS, HOLOGRAPHY, IMAGES, INPUT, INTERFACES, INTERFERENCE, INTERFEROMETRY, LIGHT, LOGIC, MICHELSON INTERFEROMETERS, MIRRORS, MIXING, MODULATION, OUTPUT, PHASE SHIFT, REFLECTION, STEADY STATE, TITANATES, NONLINEAR OPTICS, LIGHT MODULATORS, CRYSTALS, REFRACTION, GRATINGS(SPECTRA), LASER BEAMS, SYMPOSIA.
Subject Categories : Optics
Electrooptical and Optoelectronic Devices
Distribution Statement : APPROVED FOR PUBLIC RELEASE