Accession Number : ADP006795

Title :   Intensity Dependent Thresholding and Switching in the Photorefractive 'Bridge' Mutually Pumped Phase Conjugator,

Corporate Author : SOUTHAMPTON UNIV (UNITED KINGDOM) DEPT OF PHYSICS

Personal Author(s) : James, Stephen W. ; Eason, Robert W.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : The large electro-optic coefficient of photorefractive material such as barium titanate has allowed the observation of exotic phase conjugators such as the Self-Pumped Phase Conjugator(SPPC) and, more recently, the Mutually Pumped Phase Conjugator (MPPC), in which two simultaneous phase conjugate (PC) outputs are produced by the interaction of two mutually incoherent beams within a photorefractive crystal. Several generic MPPC configurations have been reported, differing more in their exact beam geometry rather than the physical mechanism responsible for the effect. These geometries include the Double Phase Conjugate Mirror (DPCM), the Mutually incoherent beam coupler (MIBC), the Bird-Wing Phase Conjugator (BWPC), the Frogs Legs Conjugator and the Bridge Conjugator. Both the DPCM and MIBC have been shown to possess input beam intensity ratio dependent reflectivities and thresholds, and these properties have been utilised in the DPCM for image processing applications. Here we report the observation of total input intensity, rather than intensity ratio, dependent reflectivity from the Bridge MPPC, which has allowed the investigation of effects such as optical thresholding, bistable and hysteretic switching, and optical flip-flop type behaviour.

Descriptors :   *IMAGE PROCESSING, *OPTICAL SWITCHING, BRIDGES, CONFIGURATIONS, CRYSTALS, IMAGES, INPUT, INTENSITY, INTERACTIONS, MATERIALS, OBSERVATION, OPTICS, OUTPUT, PHASE, PROCESSING, RATIOS, REFLECTIVITY, SWITCHING, BARIUM TITANATES, ELECTROOPTICS, OPTICAL PUMPING, REFRACTION, OPTICAL IMAGES, THRESHOLD EFFECTS, SYMPOSIA.

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE