The recently proposed method for wavelength multiplexed holograms(1) raises the fundamental issues of crosstalk and error probability in such holograms. As a result we pose the following question: A crystal with N stored λ-holograms is illuminated with, say, λ1 in order to project out (read) hologram #1.
{"title":"Crosstalk and Error Probability in Counter-Beam λ-Multiplexed Digital Holograms","authors":"A. Yariv, L. Glasser, G. Rakuljic, V. Leyva","doi":"10.1364/nlo.1992.pd15","DOIUrl":"https://doi.org/10.1364/nlo.1992.pd15","url":null,"abstract":"The recently proposed method for wavelength multiplexed holograms(1) raises the fundamental issues of crosstalk and error probability in such holograms. As a result we pose the following question: A crystal with N stored λ-holograms is illuminated with, say, λ1 in order to project out (read) hologram #1.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123531243","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. Eich, Martin Sprave, H. Mauermann, S. Stein, K. Müllen, W. Frank, T. Tschudi
NLO-chromophores of the azobenzene type and of the stilbene type have been used either as dopants or as sidegroups in polymers in order to realize NLO-materials in which the refractive index and the nonlinear susceptibility could be modified optically.1,2 These changes are based on the photochemical transformation of these molecular units from the elongated trans state to the bent cis-state. Since the trans state is the thermodynamically stable state, the cis-isomers generally undergo a thermally activated relaxation back to trans even below the glass transition temperature.3
{"title":"Studies on Novel Photoselectable Organic NLO-Molecules","authors":"M. Eich, Martin Sprave, H. Mauermann, S. Stein, K. Müllen, W. Frank, T. Tschudi","doi":"10.1364/nlo.1992.fa2","DOIUrl":"https://doi.org/10.1364/nlo.1992.fa2","url":null,"abstract":"NLO-chromophores of the azobenzene type and of the stilbene type have been used either as dopants or as sidegroups in polymers in order to realize NLO-materials in which the refractive index and the nonlinear susceptibility could be modified optically.1,2 These changes are based on the photochemical transformation of these molecular units from the elongated trans state to the bent cis-state. Since the trans state is the thermodynamically stable state, the cis-isomers generally undergo a thermally activated relaxation back to trans even below the glass transition temperature.3","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124626187","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}
G. Bourhill, F. Cruickshank, D. Pugh, G. Simpson, J. Sherwood, R. Bailey, S. Wilkie
Nitropyridine derivatives have long been known as potential materials for nonlinear optical applications [1]. The chiral molecule (+)2-(α-methylbenzylamino)-5-nitropyridine (MBA-NP) was identified as a promising material by the powder technique [2]. MBA-NP possessed a powder efficiency 20 times that of a urea reference when the fundamental wavelength was 1064 nm. This value is in good agreement with that reported by other authors [3].
{"title":"The Linear and Nonlinear Optical Properties of the Organic Material (+)2-(α-methylbenzylamino)-5-nitropyridine (MBA-NP)","authors":"G. Bourhill, F. Cruickshank, D. Pugh, G. Simpson, J. Sherwood, R. Bailey, S. Wilkie","doi":"10.1364/nlo.1992.md28","DOIUrl":"https://doi.org/10.1364/nlo.1992.md28","url":null,"abstract":"Nitropyridine derivatives have long been known as potential materials for nonlinear optical applications [1]. The chiral molecule (+)2-(α-methylbenzylamino)-5-nitropyridine (MBA-NP) was identified as a promising material by the powder technique [2]. MBA-NP possessed a powder efficiency 20 times that of a urea reference when the fundamental wavelength was 1064 nm. This value is in good agreement with that reported by other authors [3].","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125083236","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}
Dynamic photorefractive memories that store image information multiplexed in a photorefractive volume are promising for parallel information processing and computing due to their large storage capacity, fast access, and read/write/erase capability1. Incoherent erasure process can be used for updating these dynamic memories, but this process is much slower than the writing process. In contrast, selective erasure process2 based on superimposed recording of a π-phase-shifted image onto the old image is reported to be much faster than the incoherent erasure3. Arbitrary phase shift has also been investigated for optical interconnects4, assuming a grating with maximum refractive index modulation at the beginning of the selective erasure process. For dynamic photorefractive memory application it is important to understand the dynamics of the selective erasure process for multiplexed images, where each of them is characterized by a much smaller refractive index modulation. Dynamic photorefractive memory that uses π-phase-shifted selective erasure process has recently been implemented, demonstrating fast erasure capability5. In this manuscript, we analyze and confirm experimentally the dynamics of the erasure process. For simplicity and generality we assume two gratings with an arbitrary phase shift between them to be a composite grating, one being the old grating and another the new grating.
{"title":"Dynamics of composite grating in photorefractive SBN:60","authors":"H. Sasaki, J. Ma, Y. Fainman, S. H. Lee","doi":"10.1364/nlo.1992.md10","DOIUrl":"https://doi.org/10.1364/nlo.1992.md10","url":null,"abstract":"Dynamic photorefractive memories that store image information multiplexed in a photorefractive volume are promising for parallel information processing and computing due to their large storage capacity, fast access, and read/write/erase capability1. Incoherent erasure process can be used for updating these dynamic memories, but this process is much slower than the writing process. In contrast, selective erasure process2 based on superimposed recording of a π-phase-shifted image onto the old image is reported to be much faster than the incoherent erasure3. Arbitrary phase shift has also been investigated for optical interconnects4, assuming a grating with maximum refractive index modulation at the beginning of the selective erasure process. For dynamic photorefractive memory application it is important to understand the dynamics of the selective erasure process for multiplexed images, where each of them is characterized by a much smaller refractive index modulation. Dynamic photorefractive memory that uses π-phase-shifted selective erasure process has recently been implemented, demonstrating fast erasure capability5. In this manuscript, we analyze and confirm experimentally the dynamics of the erasure process. For simplicity and generality we assume two gratings with an arbitrary phase shift between them to be a composite grating, one being the old grating and another the new grating.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130191309","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}
Phase conjugated light waves reverse phase distortions in media with negligible absorption or for paraxial beam propagation [1]. We examine here a different case in which a volume conjugating medium is itself imperfect, possessing phase distortions and a conjugating efficiency dependent on grating spatial frequency. We show theoretically that for multiplexed signals, cross-talk-free phase-conjugation is obtained only for negligible spatial-frequency dispersion and a phase-conjugated reference or pump wave, and we present supporting experimental results.
{"title":"Effects of Phase Distortions in Conjugating Media","authors":"M. C. Bashaw, A. Aharoni, L. Hesselink","doi":"10.1364/nlo.1992.fa4","DOIUrl":"https://doi.org/10.1364/nlo.1992.fa4","url":null,"abstract":"Phase conjugated light waves reverse phase distortions in media with negligible absorption or for paraxial beam propagation [1]. We examine here a different case in which a volume conjugating medium is itself imperfect, possessing phase distortions and a conjugating efficiency dependent on grating spatial frequency. We show theoretically that for multiplexed signals, cross-talk-free phase-conjugation is obtained only for negligible spatial-frequency dispersion and a phase-conjugated reference or pump wave, and we present supporting experimental results.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130746485","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. Ohashi, T. Kondo, R. Ito, S. Fukatsu, Y. Shiraki, K. Kumata, S. Kano
Recently there has been considerable interest in surface-emitting second-harmonic (SH) generators fabricated from the AlxGa1-xAs system.1,2) No systematic data are available, however, on the d coefficients of AlxGa1-xAs1,3,4) A major reason for this is that many interesting semiconductors, including AlxGa1-xAs, are obtainable only in the form of a thin epitaxial layer. Furthermore, the substrate is often absorptive at SH frequencies. We have developed a new method for characterizing the optical nonlinearity of such thin-film materials on the basis of the method of reflected harmonics.5) The new method has been applied to the determination of the coefficient d14 of AlxGa1-xAs as a function of x, the AlAs composition of the alloy semiconductor.
{"title":"Quadratic Nonlinear Optical Coefficient of AlxGai-xAs Thin Film","authors":"M. Ohashi, T. Kondo, R. Ito, S. Fukatsu, Y. Shiraki, K. Kumata, S. Kano","doi":"10.1364/nlo.1992.md2","DOIUrl":"https://doi.org/10.1364/nlo.1992.md2","url":null,"abstract":"Recently there has been considerable interest in surface-emitting second-harmonic (SH) generators fabricated from the AlxGa1-xAs system.1,2) No systematic data are available, however, on the d coefficients of AlxGa1-xAs1,3,4) A major reason for this is that many interesting semiconductors, including AlxGa1-xAs, are obtainable only in the form of a thin epitaxial layer. Furthermore, the substrate is often absorptive at SH frequencies. We have developed a new method for characterizing the optical nonlinearity of such thin-film materials on the basis of the method of reflected harmonics.5) The new method has been applied to the determination of the coefficient d14 of AlxGa1-xAs as a function of x, the AlAs composition of the alloy semiconductor.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130756567","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}
The oxidation of ethanol is an important process in chemical industry where fine particles of pure silver activated by adsorbed oxygen are used as the catalyst. However two different kinds of mechanism were proposed to explain this oxidation reaction but under controversies. One is the Langmuir-Hinshewood mechanism which claimed that the ethanol molecules were firstly adsorbed on the silver surface and then reacted with the adsorbed oxygen, the other, Eley-Rideal mechanism, claimed an one-step process is active that is the ethanol molecules in gaseous state reacted directly with the adsorbed oxygen when they collided on the silver surface. Hence it is suggested to have a new technique which might be able to discriminate these two mechanisms and here, we will report our recent study on this oxidation reaction by probing with the optical technique of second harmonic generation (SHG).
{"title":"Study on the Oxidation of Chemical Compound at an Activated Polycrystalline Silver Surface Probed by SHG Technique","authors":"Jia-biao Zheng, Yanghong Liu, Wen Wang, Zhiming Zhang","doi":"10.1364/nlo.1992.tud22","DOIUrl":"https://doi.org/10.1364/nlo.1992.tud22","url":null,"abstract":"The oxidation of ethanol is an important process in chemical industry where fine particles of pure silver activated by adsorbed oxygen are used as the catalyst. However two different kinds of mechanism were proposed to explain this oxidation reaction but under controversies. One is the Langmuir-Hinshewood mechanism which claimed that the ethanol molecules were firstly adsorbed on the silver surface and then reacted with the adsorbed oxygen, the other, Eley-Rideal mechanism, claimed an one-step process is active that is the ethanol molecules in gaseous state reacted directly with the adsorbed oxygen when they collided on the silver surface. Hence it is suggested to have a new technique which might be able to discriminate these two mechanisms and here, we will report our recent study on this oxidation reaction by probing with the optical technique of second harmonic generation (SHG).","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131659822","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 recent years, efforts to exploit the third-order optical nonlinearity in devices for optical signal transmission (soliton propagation) and signal processing (nonlinear switching) have multiplied [1, 2, 3]. In contrast to the theoretical description of soliton propagation in optical fibers, the simulation of χ(3)-effects in integrated optic signal-processing components employing materials without inversion symmetry necessitates the consideration of the non-vanishing second-order nonlinear susceptibility χ(2). Here, the input optical field drives an, in general, phase-mismatched second harmonic (ω + ω → 2ω) which, in a further second-order mixing process with the input field (2ω – ω→ ω), generates a nonlinear polarization at the input field frequency. This nonlinear polarization, caused by two simultaneously occuring second-order mixing processes, combines with and modifies the effect of the directly generated third-order polarization.
{"title":"The Influence of Second Order Optical Nonlinearity on Effects of the Nonlinear Index of Refraction","authors":"R. Schiek","doi":"10.1364/nlo.1992.tud7","DOIUrl":"https://doi.org/10.1364/nlo.1992.tud7","url":null,"abstract":"In recent years, efforts to exploit the third-order optical nonlinearity in devices for optical signal transmission (soliton propagation) and signal processing (nonlinear switching) have multiplied [1, 2, 3]. In contrast to the theoretical description of soliton propagation in optical fibers, the simulation of χ(3)-effects in integrated optic signal-processing components employing materials without inversion symmetry necessitates the consideration of the non-vanishing second-order nonlinear susceptibility χ(2). Here, the input optical field drives an, in general, phase-mismatched second harmonic (ω + ω → 2ω) which, in a further second-order mixing process with the input field (2ω – ω→ ω), generates a nonlinear polarization at the input field frequency. This nonlinear polarization, caused by two simultaneously occuring second-order mixing processes, combines with and modifies the effect of the directly generated third-order polarization.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114298311","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 order to obtain second order nonlinear optical properties in doped (or functionalized) polymer films, it is necessary to orient the polar dopant molecules (poling process) and to insure a long term stability of this orientation. Other applications of organic films, such as writing polarization gratings by photoinduced anisotropy, deal with alignment of molecules (i.e. an anisotropic but centrosymmetric distribution).
{"title":"Anisotropy and Second Order Nonlinear Optical Properties Induced by Photoisomerization of Azo Dyes in polymeric films","authors":"M. Dumont, Z. Sekkat","doi":"10.1364/nlo.1992.fa5","DOIUrl":"https://doi.org/10.1364/nlo.1992.fa5","url":null,"abstract":"In order to obtain second order nonlinear optical properties in doped (or functionalized) polymer films, it is necessary to orient the polar dopant molecules (poling process) and to insure a long term stability of this orientation. Other applications of organic films, such as writing polarization gratings by photoinduced anisotropy, deal with alignment of molecules (i.e. an anisotropic but centrosymmetric distribution).","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125337979","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}
G. Duree, J. Shultz, N. Bei, G. Salamo, E. Sharp, G. Wood, R. Neurgaonkar
A physical model for the photorefractive effect consists of considering two laser beams which are allowed to cross in a photorefractive crystal, producing an interference pattern. This interference pattern, or alternating light and dark regions in the crystal, results in the selective excitation of free-carriers from impurity trapped sites in the illuminated regions into the conduction band. In the conduction band, there is a subsequent diffusion of these electrons to neighboring dark regions where they are re-trapped at empty impurity sites. This transport of charge develops a space-charge field which, at equilibrium, produces a restoring force that exactly balances the diffusive force experienced by the excited free-carriers.
{"title":"Enhanced Photorefractive Transient Response","authors":"G. Duree, J. Shultz, N. Bei, G. Salamo, E. Sharp, G. Wood, R. Neurgaonkar","doi":"10.1364/nlo.1992.wb4","DOIUrl":"https://doi.org/10.1364/nlo.1992.wb4","url":null,"abstract":"A physical model for the photorefractive effect consists of considering two laser beams which are allowed to cross in a photorefractive crystal, producing an interference pattern. This interference pattern, or alternating light and dark regions in the crystal, results in the selective excitation of free-carriers from impurity trapped sites in the illuminated regions into the conduction band. In the conduction band, there is a subsequent diffusion of these electrons to neighboring dark regions where they are re-trapped at empty impurity sites. This transport of charge develops a space-charge field which, at equilibrium, produces a restoring force that exactly balances the diffusive force experienced by the excited free-carriers.","PeriodicalId":219832,"journal":{"name":"Nonlinear Optics: Materials, Fundamentals, and Applications","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122423721","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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