A. Márquez, C. Neipp, L. Yaroslavsky, S. Gallego, M. Ortuño, A. Beléndez, I. Pascual
In this work we analyse the complex amplitude response of volume holograms. This analysis suggests a new scheme for encoding complex amplitude wavefront information onto an optical hologram which may prove useful for combining computer-generated holograms (CGH) onto volume holograms. Specifically, we analyse the amplitude and phase modulation associated with a volume phase unslanted transmission grating. Using the expressions given by the Kogelnik's coupled wave theory (KCWT) we find that there is a coupling between the amplitude and the phase modulations. This coupling can be controlled to some extent by means of the reconstruction angle: we have found that the significant magnitude is the normalized Bragg detune angle. A large variation range of the grating strength is desirable, which is enhanced by the use of shorter wavelengths, and materials exhibiting overmodulation capability and/or with a high thickness.
{"title":"Analysis of amplitude and phase coupling in volume holography","authors":"A. Márquez, C. Neipp, L. Yaroslavsky, S. Gallego, M. Ortuño, A. Beléndez, I. Pascual","doi":"10.1117/12.677159","DOIUrl":"https://doi.org/10.1117/12.677159","url":null,"abstract":"In this work we analyse the complex amplitude response of volume holograms. This analysis suggests a new scheme for encoding complex amplitude wavefront information onto an optical hologram which may prove useful for combining computer-generated holograms (CGH) onto volume holograms. Specifically, we analyse the amplitude and phase modulation associated with a volume phase unslanted transmission grating. Using the expressions given by the Kogelnik's coupled wave theory (KCWT) we find that there is a coupling between the amplitude and the phase modulations. This coupling can be controlled to some extent by means of the reconstruction angle: we have found that the significant magnitude is the normalized Bragg detune angle. A large variation range of the grating strength is desirable, which is enhanced by the use of shorter wavelengths, and materials exhibiting overmodulation capability and/or with a high thickness.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131759016","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}
S. Gallego, M. Ortuño, C. Neipp, A. Márquez, J. Kelly, J. Sheridan, A. Beléndez, I. Pascual
Research dealing with models to predict and understand the behaviour of photopolymers have generated many interesting studies considering a 2-dimensional geometry. These models suppose that the photopolymer layer is homogeneous in depth. Using this approximation good results can be obtained if the thickness of photopolymers is less than 200 μm. However, it is well known that Lambert-Beer's law predicts an exponential decay of the light inside the material. In recent years intensive efforts have been made to develop new holographic memories based on photopolymers. For this application the thickness of the layer is increased, usually to more than 500 μm, and Lambert-Beer's law plays a significant role in the recording step. The attenuation of the index profile inside these materials has been measured, showing that it is an important phenomenon. This attenuation limits the maximum effective optical thickness of the grating and shows that the 2-D models can not be applied in these cases. For this reason in this work a 3-dimensional model is presented to analyze the real behaviour of the photopolymers and study the variations in the index profile in depth. In this work we examine the predictions of the model in the case of a general dependence of the polymerisation rate with respect to the intensity pattern, and the effects of varying the exposure intensity are also compared in 3-D cases. Finally, the limitation of the data storage capacity of the materials due to the Lambert-Beer law is evaluated.
{"title":"3D behaviour of photopolymers as holographic recording material","authors":"S. Gallego, M. Ortuño, C. Neipp, A. Márquez, J. Kelly, J. Sheridan, A. Beléndez, I. Pascual","doi":"10.1117/12.676525","DOIUrl":"https://doi.org/10.1117/12.676525","url":null,"abstract":"Research dealing with models to predict and understand the behaviour of photopolymers have generated many interesting studies considering a 2-dimensional geometry. These models suppose that the photopolymer layer is homogeneous in depth. Using this approximation good results can be obtained if the thickness of photopolymers is less than 200 μm. However, it is well known that Lambert-Beer's law predicts an exponential decay of the light inside the material. In recent years intensive efforts have been made to develop new holographic memories based on photopolymers. For this application the thickness of the layer is increased, usually to more than 500 μm, and Lambert-Beer's law plays a significant role in the recording step. The attenuation of the index profile inside these materials has been measured, showing that it is an important phenomenon. This attenuation limits the maximum effective optical thickness of the grating and shows that the 2-D models can not be applied in these cases. For this reason in this work a 3-dimensional model is presented to analyze the real behaviour of the photopolymers and study the variations in the index profile in depth. In this work we examine the predictions of the model in the case of a general dependence of the polymerisation rate with respect to the intensity pattern, and the effects of varying the exposure intensity are also compared in 3-D cases. Finally, the limitation of the data storage capacity of the materials due to the Lambert-Beer law is evaluated.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124673081","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 aim of this work is to understand the effects of the shrinkage phenomenon in H-PDLC reflection gratings through the realtime analysis of their transmission spectra during the recording process. The realtime spectroscopic analysis of the samples showed a light intensity dependent free-radical polymerization indicated by a quick growth of the reflection peak whose corresponding diffraction efficiency, measured at normal incidence, is in the range of 40%-45% depending on the photopolymerization conditions. An optical shrinkage corresponding to a 4.3% displacement of the reflected wavelength from the expected value has been detected. This value of the shrinkage is in agreement to that mesaured in a similar system.
{"title":"Spectral analysis of shrinkage in holographic materials suitable for optical storage applications","authors":"L. Criante, K. Beev, D. Lucchetta, F. Simoni","doi":"10.1117/12.676538","DOIUrl":"https://doi.org/10.1117/12.676538","url":null,"abstract":"The aim of this work is to understand the effects of the shrinkage phenomenon in H-PDLC reflection gratings through the realtime analysis of their transmission spectra during the recording process. The realtime spectroscopic analysis of the samples showed a light intensity dependent free-radical polymerization indicated by a quick growth of the reflection peak whose corresponding diffraction efficiency, measured at normal incidence, is in the range of 40%-45% depending on the photopolymerization conditions. An optical shrinkage corresponding to a 4.3% displacement of the reflected wavelength from the expected value has been detected. This value of the shrinkage is in agreement to that mesaured in a similar system.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131571116","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 DOE-HOE's, made by Dot-matrix technology, have found application in various areas, such as security, protection of various goods from faking, packing etc. These holograms contain a set of pixels with diffraction gratings with different spatial frequencies and orientation. The process of manufacturing represents a consecutive pixels exposure. The pixels quantity is great (about 105-106), that's why master-shim manufacturing requires considerable time. Spatial frequency and orientation of gratings change because of mechanical shift of elements. For acceleration of the recording process it is necessary to replace slow mechanical devices with high-speed ones. This paper proposes a possible solution of this problem, by using a spatial light modulator. This paper describes the technique and results of calculations of optical components parameters.
{"title":"The optical system of the stand for DOE-HOE producing with a liquid crystal spatial light modulator","authors":"Ivan Tsiganov, S. Odinokov, A. Nikolaev","doi":"10.1117/12.677186","DOIUrl":"https://doi.org/10.1117/12.677186","url":null,"abstract":"The DOE-HOE's, made by Dot-matrix technology, have found application in various areas, such as security, protection of various goods from faking, packing etc. These holograms contain a set of pixels with diffraction gratings with different spatial frequencies and orientation. The process of manufacturing represents a consecutive pixels exposure. The pixels quantity is great (about 105-106), that's why master-shim manufacturing requires considerable time. Spatial frequency and orientation of gratings change because of mechanical shift of elements. For acceleration of the recording process it is necessary to replace slow mechanical devices with high-speed ones. This paper proposes a possible solution of this problem, by using a spatial light modulator. This paper describes the technique and results of calculations of optical components parameters.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115227318","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}
We demonstrate the possibility of photodimerizable chromophores attached to a short alkyl chain as a potential medium for high capacity digital optical storage. A large increase in transmission from 4% to 70% is obtained in 20 s when irradiated with a 5 mW unfocused laser beam at 257 nm in a thin film of 1-(6-Bromohexyl)uracil. Through theoretical simulations, we show that the interaction cross-section is 6 10-18 cm2 at a photon dose of 9 1016 photons cm-2 s-1. We also investigate the formation of holographic diffraction grating in a film, obtaining an efficiency of 16%, mainly due to a surface relief grating.
{"title":"Organic materials for UV holographic and digital storage","authors":"P. Ramanujam, B. Lohse, R. Berg","doi":"10.1117/12.677015","DOIUrl":"https://doi.org/10.1117/12.677015","url":null,"abstract":"We demonstrate the possibility of photodimerizable chromophores attached to a short alkyl chain as a potential medium for high capacity digital optical storage. A large increase in transmission from 4% to 70% is obtained in 20 s when irradiated with a 5 mW unfocused laser beam at 257 nm in a thin film of 1-(6-Bromohexyl)uracil. Through theoretical simulations, we show that the interaction cross-section is 6 10-18 cm2 at a photon dose of 9 1016 photons cm-2 s-1. We also investigate the formation of holographic diffraction grating in a film, obtaining an efficiency of 16%, mainly due to a surface relief grating.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116711476","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 is well known that dichromated gelatin is one of the best materials for phase hologram recording. Several competing hypotheses for the nature ofthe photoinduced response in DCG have been discussed in the literature, and still there is no generally accepted point of view. Recently we have demonstrated how the optical response of DCG holograms can be analyzed on the basis of light scattering from nano-voids, which appear in the process of hologram formation. We have assumed that the voids are ellipsoids with dimensions of 10 - 40 nm, i.e. we are within the approximations of Raleigh scattering. Here, we analyze the DCG reflection hologram performance in terms of rigorous theory of light scattering with no limitations for the size of the voids. Mathematical simulations of the reflection spectra give a plausible quantitative explanation of many experimental facts related to DCG holograms obtained by the so-called 'drastic' chemical treatment after exposure.
{"title":"DCG holograms as nanosized composite film elements","authors":"P. Sharlandjiev, B. Markova","doi":"10.1117/12.677001","DOIUrl":"https://doi.org/10.1117/12.677001","url":null,"abstract":"It is well known that dichromated gelatin is one of the best materials for phase hologram recording. Several competing hypotheses for the nature ofthe photoinduced response in DCG have been discussed in the literature, and still there is no generally accepted point of view. Recently we have demonstrated how the optical response of DCG holograms can be analyzed on the basis of light scattering from nano-voids, which appear in the process of hologram formation. We have assumed that the voids are ellipsoids with dimensions of 10 - 40 nm, i.e. we are within the approximations of Raleigh scattering. Here, we analyze the DCG reflection hologram performance in terms of rigorous theory of light scattering with no limitations for the size of the voids. Mathematical simulations of the reflection spectra give a plausible quantitative explanation of many experimental facts related to DCG holograms obtained by the so-called 'drastic' chemical treatment after exposure.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124995185","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}
F. Crompvoets, F. Schuurmans, M. Balistreri, T. Tukker, G. t'Hooft, S. Stallinga
A simple, diffraction limited, optical design for a Holographic Data Storage System with a high numerical aperture and large field is presented. A system analysis is performed and the design is compared with different current and future formats for optical data storage.
{"title":"High-numerical aperture holographic data storage","authors":"F. Crompvoets, F. Schuurmans, M. Balistreri, T. Tukker, G. t'Hooft, S. Stallinga","doi":"10.1117/12.677016","DOIUrl":"https://doi.org/10.1117/12.677016","url":null,"abstract":"A simple, diffraction limited, optical design for a Holographic Data Storage System with a high numerical aperture and large field is presented. A system analysis is performed and the design is compared with different current and future formats for optical data storage.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123414358","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 discusses the necessities for holograms to be generated in realtime for both telecommunications and video applications. Implications for implementing a fixed-point version of Direct Binary Search (DBS) in silicon studied, along with a more detailed look at the implementation and results collected for a realtime DBS method in a Field Programmable Gate Array (FPGA). The paper looks forward to future architectures and makes suggestions based on the trend of capabilities of FPGAs.
{"title":"Realtime hologram generation using iterative methods","authors":"P. Mash, T. Wilkinson","doi":"10.1117/12.677167","DOIUrl":"https://doi.org/10.1117/12.677167","url":null,"abstract":"This paper discusses the necessities for holograms to be generated in realtime for both telecommunications and video applications. Implications for implementing a fixed-point version of Direct Binary Search (DBS) in silicon studied, along with a more detailed look at the implementation and results collected for a realtime DBS method in a Field Programmable Gate Array (FPGA). The paper looks forward to future architectures and makes suggestions based on the trend of capabilities of FPGAs.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116054951","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}
Three electronic speckle pattern shearing interferometers (ESPSI) using photopolymer holographic gratings to produce the sheared image are presented. In the first ESPSI system two holographic gratings are used. The gratings are placed between the object and an imaging lens in front of the CCD camera. In the second ESPSI system one grating is used in combination with a sheet of ground glass. The sheared images on the ground glass are further imaged onto a CCD camera. In the third ESPSI system only one grating is used - it is placed in front of the object. The image and the sheared image are imaged onto the CCD camera, whose optical axis coincides with the normal to the object surface. The introduction of photopolymer holographic gratings in ESPSI systems gives the advantage of using high aperture optical elements at relatively low price. The systems are compared in terms of flexibility in their adjustment, sensitivity, suitability and limitations for different applications.
{"title":"Comparison of three electronic speckle pattern shearing interferometers using photopolymer holographic optical elements","authors":"E. Mihaylova, I. Naydenova, S. Martin, V. Toal","doi":"10.1117/12.677189","DOIUrl":"https://doi.org/10.1117/12.677189","url":null,"abstract":"Three electronic speckle pattern shearing interferometers (ESPSI) using photopolymer holographic gratings to produce the sheared image are presented. In the first ESPSI system two holographic gratings are used. The gratings are placed between the object and an imaging lens in front of the CCD camera. In the second ESPSI system one grating is used in combination with a sheet of ground glass. The sheared images on the ground glass are further imaged onto a CCD camera. In the third ESPSI system only one grating is used - it is placed in front of the object. The image and the sheared image are imaged onto the CCD camera, whose optical axis coincides with the normal to the object surface. The introduction of photopolymer holographic gratings in ESPSI systems gives the advantage of using high aperture optical elements at relatively low price. The systems are compared in terms of flexibility in their adjustment, sensitivity, suitability and limitations for different applications.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122626885","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}
E. Vasilyev, V. Shelkovnikov, E. Pen, A. I. Plechanov
Dynamics of pulse holographic recording of diffraction gratings has been studied in photopolymer material: polyvinyl alcohol (binder), acrylamide (monomer), Erythrosine (dye-sensitizer), triethanolamine (donor-initiator). Pulse duration of the 2nd harmonic of Nd:YAG laser is 10 ns. A formation of polymer (permanent) and primary gratings were observed after pulse. Photopolymer composition optimization has been provided within conditions of pulse recording. Kinetics models of photopolymer formation subject to radical death due to recombination and purity have been compared with experimental data.
{"title":"Pulse recording dynamics of diffraction gratings in xanthene dyes sensitized photopolymer material","authors":"E. Vasilyev, V. Shelkovnikov, E. Pen, A. I. Plechanov","doi":"10.1117/12.676533","DOIUrl":"https://doi.org/10.1117/12.676533","url":null,"abstract":"Dynamics of pulse holographic recording of diffraction gratings has been studied in photopolymer material: polyvinyl alcohol (binder), acrylamide (monomer), Erythrosine (dye-sensitizer), triethanolamine (donor-initiator). Pulse duration of the 2nd harmonic of Nd:YAG laser is 10 ns. A formation of polymer (permanent) and primary gratings were observed after pulse. Photopolymer composition optimization has been provided within conditions of pulse recording. Kinetics models of photopolymer formation subject to radical death due to recombination and purity have been compared with experimental data.","PeriodicalId":266048,"journal":{"name":"International Conference on Holography, Optical Recording, and Processing of Information","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128532857","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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