Impurity doping of bismuth germanium oxide (BGO) has been found to yield large impovements in the photorefractive sensitivity (S1). A 17 fold increase over BGO has been obtained with fully titanium substituted BGO. This improvement is manifested as a simultaneous enhancement of the saturation diffraction efficiency and reduction of the characteristic time constant of the material. We suggest that the former arises from an increase in the effective electrooptic coefficient though the mechanism giving rise to the reduced time constant is as yet unknown.
{"title":"Optimization Of Photorefractive Sillenites","authors":"M. Powell, R. Wright","doi":"10.1117/12.941596","DOIUrl":"https://doi.org/10.1117/12.941596","url":null,"abstract":"Impurity doping of bismuth germanium oxide (BGO) has been found to yield large impovements in the photorefractive sensitivity (S1). A 17 fold increase over BGO has been obtained with fully titanium substituted BGO. This improvement is manifested as a simultaneous enhancement of the saturation diffraction efficiency and reduction of the characteristic time constant of the material. We suggest that the former arises from an increase in the effective electrooptic coefficient though the mechanism giving rise to the reduced time constant is as yet unknown.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114183340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Focal lines of arbitrary position and orientation even parallel to the optical axis may be used in a variety of situations, such as display of 3-D images, contouring of inclined surfaces and holographic optical elements. A synthetic generation using a computer is promising because of the flexibility. Then, the wave propagation has to be simulated. We present a calculation by use of the stationary phase method and show the analogy to the solution of the wave equation. A cube composed of line segments is recorded in a hologram and reconstructed optically. For each line segment, a second line foci occurs in the Fourier plane of the hologram which causes irritation when the image is visually observed. Superposition of a slight random phase variation removes the ambiguity and allows secure accomodation. Intensity variations along the line segment can be introduced by superposition of several distributions which reconstruct the same line segment. A further generalization may be achieved to reconstruct nonstraight focal lines in 3-D.
{"title":"Free Positioned And Oriented Focal Lines From Computer-Generated Holograms","authors":"D. Leseberg, C. Frère","doi":"10.1117/12.941624","DOIUrl":"https://doi.org/10.1117/12.941624","url":null,"abstract":"Focal lines of arbitrary position and orientation even parallel to the optical axis may be used in a variety of situations, such as display of 3-D images, contouring of inclined surfaces and holographic optical elements. A synthetic generation using a computer is promising because of the flexibility. Then, the wave propagation has to be simulated. We present a calculation by use of the stationary phase method and show the analogy to the solution of the wave equation. A cube composed of line segments is recorded in a hologram and reconstructed optically. For each line segment, a second line foci occurs in the Fourier plane of the hologram which causes irritation when the image is visually observed. Superposition of a slight random phase variation removes the ambiguity and allows secure accomodation. Intensity variations along the line segment can be introduced by superposition of several distributions which reconstruct the same line segment. A further generalization may be achieved to reconstruct nonstraight focal lines in 3-D.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115928534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has been shown that synthetic phase-only filter formed by using different plane wave carriers may provide very high optical efficiency and can produce very sharp correlation peaks in the case of multiobjects correlation recognition. Binarizing the synthetic phase-only filter (SPOF) would make filter making much more easy. But binary synthetic phase-only filter (BSPOF) would produce undesirable noise which mainly consists of convolution-like peaks in the output plane. These noise peaks may sometime rise very high especially when objects are symmetrical. In this paper a random phase mask placed close to the BSPOF in the Fourier plane is used in the correlation system. It can spread the energy of the noise peaks in the output plane. So that, there is no any obvious noise peaks presented, however, at the same time, the sharp correlation-like peaks of SPOF are remained very well. The computer simulation results are given. The comparison of the correlation outputs of BSPOF with that of SPOF is discussed. And 3-D plots of correlation output are presented.
{"title":"Binary Synthetic Phase-Only Filter (BSPOF) With Random Mask","authors":"G. Zhang, X. Su, L. R. Guo","doi":"10.1117/12.941623","DOIUrl":"https://doi.org/10.1117/12.941623","url":null,"abstract":"It has been shown that synthetic phase-only filter formed by using different plane wave carriers may provide very high optical efficiency and can produce very sharp correlation peaks in the case of multiobjects correlation recognition. Binarizing the synthetic phase-only filter (SPOF) would make filter making much more easy. But binary synthetic phase-only filter (BSPOF) would produce undesirable noise which mainly consists of convolution-like peaks in the output plane. These noise peaks may sometime rise very high especially when objects are symmetrical. In this paper a random phase mask placed close to the BSPOF in the Fourier plane is used in the correlation system. It can spread the energy of the noise peaks in the output plane. So that, there is no any obvious noise peaks presented, however, at the same time, the sharp correlation-like peaks of SPOF are remained very well. The computer simulation results are given. The comparison of the correlation outputs of BSPOF with that of SPOF is discussed. And 3-D plots of correlation output are presented.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134176092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we discuss enhancement techniques for use with BSO and Ga As. These techniques include application of electric fields both a.c. and d.c. We consider the effects of crystal orientation and of beam polarisation and present results for two wave mixing in BSO and Ga As. For Ga As results we propose absorption gratings to fully explain our results. We show that the 43m structure of Ga As makes,it ideally suited for a four-wave mixing configuration with positive feedback.
{"title":"Optimisation Of Two And Four Wave Mixing Processes In Photorefractive Materials","authors":"K. Walsh, P. Foote, T. J. Hall","doi":"10.1117/12.941606","DOIUrl":"https://doi.org/10.1117/12.941606","url":null,"abstract":"In this paper we discuss enhancement techniques for use with BSO and Ga As. These techniques include application of electric fields both a.c. and d.c. We consider the effects of crystal orientation and of beam polarisation and present results for two wave mixing in BSO and Ga As. For Ga As results we propose absorption gratings to fully explain our results. We show that the 43m structure of Ga As makes,it ideally suited for a four-wave mixing configuration with positive feedback.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"201 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121280251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Nicholson, G. Gibbons, I. R. Cooper, C. R. Petts
Coherent optical image correlators have been the subject of much research since the early work, performed by Vander Lugt in 1964 [1]. The use of conventional holographic techniques in such systems have proven to be inflexible in that the filter function cannot be updated at a speed comparable to that of the processing speed.
{"title":"An Updateable Image Correlator Employing Synthetic Discriminant Functions","authors":"M. Nicholson, G. Gibbons, I. R. Cooper, C. R. Petts","doi":"10.1117/12.941607","DOIUrl":"https://doi.org/10.1117/12.941607","url":null,"abstract":"Coherent optical image correlators have been the subject of much research since the early work, performed by Vander Lugt in 1964 [1]. The use of conventional holographic techniques in such systems have proven to be inflexible in that the filter function cannot be updated at a speed comparable to that of the processing speed.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133859432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A system based on multiplex holography has been developed for the display and storage of three-dimensional information. Volume ('stack') multiplex holograms have been produced for viewing on a novel white light display device based on dispersion compensation. The image processing and holographic techniques developed to optimise these results are described. The demonstration of potential applications of the displays for data from medical imaging, analytical techniques such as electron microscopy and scientific data analysis is detailed.
{"title":"Multiplex Holography For The Display Of Three-Dimensional Information","authors":"J. Drinkwater, S. Hart","doi":"10.1117/12.941626","DOIUrl":"https://doi.org/10.1117/12.941626","url":null,"abstract":"A system based on multiplex holography has been developed for the display and storage of three-dimensional information. Volume ('stack') multiplex holograms have been produced for viewing on a novel white light display device based on dispersion compensation. The image processing and holographic techniques developed to optimise these results are described. The demonstration of potential applications of the displays for data from medical imaging, analytical techniques such as electron microscopy and scientific data analysis is detailed.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"14 18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114854491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Techniques for production of holographic stereograms are described with special attention given to stereograms with computer-generated graphics. Photographic techniques and equipment for recording computer graphic imHLges are discussed. Applications in various fields are reviewed.
{"title":"Holographic Stereograms From Computer Generated Images","authors":"Craig D. Newswanger, C. Outwater, David E. Coons","doi":"10.1117/12.941628","DOIUrl":"https://doi.org/10.1117/12.941628","url":null,"abstract":"Techniques for production of holographic stereograms are described with special attention given to stereograms with computer-generated graphics. Photographic techniques and equipment for recording computer graphic imHLges are discussed. Applications in various fields are reviewed.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125479690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Rupp, J. Marotz, K. Ringhofer, S. Treichel, S. Feng, E. Kratzig
We present experimental evidence that reflection at the crystal back face due to the large refractive indices of LiNbO3 and LiTaO3 is responsible for strong holographic scattering effects. By these means four-wave interaction phenomena occur. The light is isotropically scattered (equal polarization of incident and scattered wave) in a cone emerging in forward and backward direction from the sample with a cone angle equal to the angle of reflection. We explain the geometry of the patterns produced by the incident reflected and scattered beams and investigate the angular and time dependence of the scattered light.
{"title":"Four-Wave Interaction Phenomena In Holographic Scattering","authors":"R. Rupp, J. Marotz, K. Ringhofer, S. Treichel, S. Feng, E. Kratzig","doi":"10.1117/12.941598","DOIUrl":"https://doi.org/10.1117/12.941598","url":null,"abstract":"We present experimental evidence that reflection at the crystal back face due to the large refractive indices of LiNbO3 and LiTaO3 is responsible for strong holographic scattering effects. By these means four-wave interaction phenomena occur. The light is isotropically scattered (equal polarization of incident and scattered wave) in a cone emerging in forward and backward direction from the sample with a cone angle equal to the angle of reflection. We explain the geometry of the patterns produced by the incident reflected and scattered beams and investigate the angular and time dependence of the scattered light.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122534762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Bondiou, J. de Bougrenet de la Tocnaye, P. Pellat-Finet
A photorefractive BSO crystal used as a light amplifier within an optical fibre ring cavity forms an optical oscillator whose transverse modes are the modes of the optical fibre. Several intracavity filtering techniques can thence be considered in order to select any particular transverse mode among the others, thus achieving an active generator of pure and isolated optical fibre modes.
{"title":"Generator Of Optical Fibre Modes Using A Photorefractive Crystal","authors":"M. Bondiou, J. de Bougrenet de la Tocnaye, P. Pellat-Finet","doi":"10.1117/12.941611","DOIUrl":"https://doi.org/10.1117/12.941611","url":null,"abstract":"A photorefractive BSO crystal used as a light amplifier within an optical fibre ring cavity forms an optical oscillator whose transverse modes are the modes of the optical fibre. Several intracavity filtering techniques can thence be considered in order to select any particular transverse mode among the others, thus achieving an active generator of pure and isolated optical fibre modes.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115148547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper examines holographic mirrors used in Holographic Night Vision Goggles (HNVG). The characteristics of the DOEs such as diffraction efficiency, spectral bandwidth and homogeneity have been investigated experimentally. These performances have been tested in a geometry which simulates as close as possible the operating conditions of the HNVG. The advantages of this approach are discussed in comparision with the commonly used technique of characterization.
{"title":"Characterization Measurements Of Holographic Mirrors","authors":"J. Bézy, 0. Dupont, P. Adam, E. Schweicher","doi":"10.1117/12.941618","DOIUrl":"https://doi.org/10.1117/12.941618","url":null,"abstract":"This paper examines holographic mirrors used in Holographic Night Vision Goggles (HNVG). The characteristics of the DOEs such as diffraction efficiency, spectral bandwidth and homogeneity have been investigated experimentally. These performances have been tested in a geometry which simulates as close as possible the operating conditions of the HNVG. The advantages of this approach are discussed in comparision with the commonly used technique of characterization.","PeriodicalId":127161,"journal":{"name":"Hague International Symposium","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133914653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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