Dissertations / Theses on the topic 'Synthetic holography'

Afin d’améliorer l’expérience utilisateur de leurs véhicules, les constructeurs automobiles recherchent des systèmes d’affichage et de contrôles innovants, tels des dispositifs permettant de produire des images 3D. Pour ceci, l’holographie est une solution a priori très performante car elle permet de générer une scène 3D incluant la majorité des indices de perception de la 3D nécessaire au cerveau humain. Si la production en série d’hologrammes « classiques » (i.e. à enregistrement optique) est trop contraignante pour les applications automobiles, les hologrammes synthétiques en relief de surface sont compatibles avec la technique de nano-imprint et peuvent donc aisément être produits en grande série. Mais le milieu automobile impose de plus de fortes contraintes de coût, de compacité du système et de sécurité oculaire. Le recours à une illumination LED des hologrammes est donc largement préférable à l’illumination laser généralement utilisée. Une solution holographique illuminé par LED et générant la perception d’un objet flottant, dans le cadre d’une application d’IHM intérieure au véhicule est démontrée. La réalisation d’une étude statistique confirmant que la grande majorité des observateurs perçoivent la scène 3D flottante correctement est détaillée et discutée. Enfin, la démonstration d’une extension de l’approche encore plus compacte en permettant l’illumination par de multiples sources LED distinctes d’un hologramme synthétique générant une image flottante perçue en 3D est présentée
To improve the user experience in their vehicles, automotive manufacturers are searching for innovative display and control systems, such as devices producing 3D images. Holography is an attractive solution as it can generate 3D scenes incorporating most of the perceptual cues necessary for the human brain. While mass production of "classic" holograms (i.e., optically recorded) for automotive applications has strong constraints, surface relief synthetic holograms are compatible with nano-imprint technology, allowing easy large-scale production. However, the automotive environment imposes additional constraints of cost, system compactness, and eye safety. In this automotive context, the use of LED illumination for holograms is therefore highly preferable to the commonly used laser illumination. We demonstrate an LED illuminated holographic solution that creates the perception of a floating object, targeting an in-vehicle human-machine interface (HMI) application. We also present a statistical study confirming that a large majority of observers perceive the floating 3D scene correctly. Finally, we demonstrate an even more compact extension of the approach enabling simultaneous illumination by multiple distinct LED sources of a single synthetic hologram, generating the perception of floating 3D image

L’holographie est souvent considérée comme la technologie de visualisation 3D la plus prometteuse, puisqu'elle fournit l'illusion du relief la plus naturelle et la plus réaliste possible. Toutefois, pour trouver application dans le domaine de la visioconférence ou de la téléprésence, les méthodes de génération numérique d'hologrammes doivent produire des scènes réalistes avec une forte illusion de profondeur, et ce en temps réel. Cette thèse se situe dans ce contexte et est organisé en deux parties. Dans la première partie de ce travail, nous avons proposé deux algorithmes de synthèse d'hologrammes permettant de se rapprocher du temps réel. Tout d'abord, nous avons développé une méthode combinant deux approches complémentaires: les approches point-source et wave-field. Alors que les méthodes de l'état de l'art réduisent la complexité de calcul de ces deux approches indépendamment, notre méthode tire parti de chacune d'entre elles. De cette manière, le temps de calcul de l'hologramme a été réduit de plus de 65% par rapport aux méthodes point-source et wave-field conventionnelles. Deuxièmement, nous avons cherché à accélérer cette méthode hybride en supprimant les redondances temporelles entre les trames consécutives d'une vidéo 3D. Pour chaque image, l'algorithme détecte les changements dans la scène et met à jour l'hologramme des points affectés. Étant donné que seules de petites régions de l'hologramme sont mises à jour, la charge de calcul est considérablement réduite, permettant le calcul d’hologrammes couleur à 60 images par seconde. Dans la deuxième partie de ce travail, nous avons proposé deux algorithmes afin d'améliorer la qualité visuelle des scènes. Tout d'abord, nous avons perfectionné la méthode hybride pour tenir compte des occultations dans la scène. Pour cela, nous avons conçu une méthode efficace pour le calcul de l'occultation d'une onde lumineuse par un point. Cette méthode reproduit les occultations sans augmenter de manière significative le temps de calcul de la méthode hybride originale. Enfin, nous avons proposé une méthode pour le calcul d'un hologramme à partir de données multivue-plus-profondeur (MVD) avec prise en compte des réflexions spéculaires. Selon cette méthode, la géométrie de la scène est reconstruite à partir des données MVD sous la forme d'un nuage de points, ce qui permet de n'utiliser que quelques projections de la scène. En outre, afin de tenir compte de réflexions spéculaires, chaque point de la scène est considéré avoir une émission différente selon les directions. Enfin, la lumière émise par la scène est propagée dans le plan de l'hologramme. Les résultats expérimentaux montrent que cette méthode reproduit tous les indices de la profondeur et l'illumination précise de la scène avec une complexité de calcul réduite
Holography is often considered as the most promising 3D visualization technology, since it can produce the most realistic and natural depth illusion to the naked eye. However, in order to have application in the field of videoconferencing or telepresence systems, hologram synthesis methods should be able to produce realistic 3D scenes with strong depth illusion in real-time. This thesis falls within this context and is organized into two parts. In the first part of this work, we investigated two novel algorithms in order to get closer to real-time computation. First, we designed a fast hologram calculation method by combining two approaches which complement one another: the point-source and wave-field approaches. Whereas previously proposed methods reduced the computational complexity of these approaches independently, our method takes advantages from both of them. By this way, the hologram calculation time has been reduced by more than 65% compare to the conventional point-source and wave-field methods. Second, we further accelerated this hybrid method by removing temporal redundancies between consecutive frames of a 3D video. For each video frame, the algorithm detects changes in the scene and updates the hologram of only affected scene points. Since only small regions of the hologram are updated at each video frame, this method allows the computational burden to be dramatically reduced, enabling the computation of colorful video holograms at 60 frames per second. In the second part of this work, we proposed two algorithms in order to enhance the visual quality of displayed scenes. First, we improved the hybrid method to take into account occlusions between objects in the scene. To this end, we designed an efficient algorithm for light shielding between points and light waves. Experimental results revealed that this method provides occlusion effect without significantly increasing the hologram calculation time of the original hybrid method. Finally, we proposed a hologram computation method from Multiview-plus-depth (MVD) data with rendering of specular reflections. In this method, the 3D scene geometry is first reconstructed from the MVD data as a layered point-cloud, enabling the use of only a few perspective projections of the scene. Furthermore, in order to take into account specular reflections, each scene point is considered to emit light differently in all the directions. Finally, light scattered by the scene is numerically propagated towards the hologram plane in order to get the final hologram. Experimental results show that the proposed method is able to provide all the human depth cues and accurate shading of the scene with reduced computational complexity

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1987.
Bibliography: leaves 54-55.
A digital image processing technique is presented that allows conventionally produced images to be prepared for undistorted printing in one-step holographic stereograms. This technique effectively predistorts the source 2D image set for a holographic stereogram to compensate for the distorting effects of its display geometry. The resulting stereograms can have undistort ed images that occupy space in front, back, and through the hologram surface. This technique is much more convenient that the current alternatives which either require unusual large optics, or much more intensive use of computer resources. It should therefore facilitate the fast and convenient production of one-step stereograms which are excellent 3D hardcopy displays with potential for applications that require fast visual communication of complex 3D information.
by Mark Holzbach.
M.S.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Synthetic-aperture microwave imaging with ground penetrating radar systems has become a research topic of great importance for the potential applications in sensing and profiling of civil and geophysical structures. It allows us to visualize subsurface structures for nondestructive evaluation with microwave tomographic images. This paper provides an overview of the research program, ranging from the formation of the concepts, physical and mathematical modeling, formulation and development of the image reconstruction algorithms, laboratory experiments, and full-scale field tests.

To date electric pianos and samplers tend to concentrate on authenticity in terms of temporal and spectral aspects of sound. However, they barely recreate the original sound radiation characteristics, which contribute to the perception of width and depth, vividness and voice separation, especially for instrumentalists, who are located near the instrument. To achieve this, a number of sound field measurement and synthesis techniques need to be applied and adequately combined. In this paper we present the theoretic foundation to combine so far isolated and fragmented sound field analysis and synthesis methods to realize a radiation keyboard, an electric harpsichord that approximates the sound of a real harpsichord precisely in time, frequency, and space domain. Potential applications for such a radiation keyboard are conservation of historic musical instruments, music performance, and psychoacoustic measurements for instrument and synthesizer building and for studies of music perception, cognition, and embodiment.

Les éléments optiques diffractifs (EOD) sont maintenant largement utilisés dans les applications universitaires et industrielles grâce à leurs caractéristiques ultra-minces et compactes et à leur très flexible manipulation des fronts d'ondes lumineuses. Malgré ces excellentes propriétés, la portée d'application des EOD est souvent limitée par le fait que la plupart des DOE sont conçus pour générer uniquement des motifs projetés en 2D, et plus important encore, pour être utilisés uniquement avec des sources laser monochromatiques, cohérentes, souvent collimatées. Les contraintes de coût et de sécurité oculaire des sources laser limitent fortement les applications de visualisation des EOD telles que les hologrammes de sécurité, et la nature 2D des motifs générés limite les applications de réalité virtuelle ou augmentée. Pour surmonter ces restrictions, cette thèse vise la conception et la fabrication de structures diffractives 3D sélectives en longueur d'onde qui peuvent produire un objet 3D "flottant" perçu à plusieurs angles de vue derrière le substrat EOD lorsqu'il est éclairé par des sources LED blanches facilement disponibles et bon marché. Dans une première approche, nous développons et validons expérimentalement une série de nouveaux algorithmes de conception pour des structures EOD conventionnelles, optiquement "minces" sous un éclairage incohérent et divergent ; d'abord pour projeter des motifs 2D, puis pour créer des images 2D virtuelles et enfin des motifs 3D virtuels. Dans un deuxième temps, nous exploitons les capacités des structures optiquement "épaisses" de type Bragg pour introduire une sélectivité spectrale (vers des modèles de sortie de couleur) et améliorer l'efficacité de la diffraction. Comme l'approximation des éléments minces n'est pas valable pour la conception de structures photoniques 3D optiquement épaisses, nous développons un algorithme d'optimisation des essaims de particules basé sur un modèle de diffraction rigoureux pour concevoir des structures diffractives synthétiques optiquement épaisses très innovantes. La fabrication rentable de ces structures micro et nano-photoniques entièrement 3D proposées est très difficile lorsqu'on utilise les techniques lithographiques traditionnelles actuelles qui sont généralement limitées, en pratique, à la fabrication de structures 2D ou 2,5D. À cette fin, le département d'optique de l'IMT Atlantique met actuellement au point un prototype avancé de photoplotter de polymérisation à deux photons massivement parallélisés (2PP) pour la fabrication de structures photoniques entièrement tridimensionnelles de grande surface. Nous présentons nos contributions à la conception et au développement des modules d'illumination critiques et de haute uniformité pour le nouveau prototype de photoplotteur 2PP. La recherche et le développement de cette thèse contribuent à l'élargissement des applications de l'EOD à des domaines actuellement inaccessibles. Les méthodes de conception développées peuvent également trouver des applications dans des domaines d'affichage holographique tels que la réalité augmentée automobile
Diffractive Optical Elements (DOEs) are now widely used in academic and industrial applications due to their ultrathin, compact characteristics and their highly flexible manipulation of light wave-fronts. Despite these excellent properties, the scope of DOE applications is often limited by the fact that most DOEs are designed to generate only 2D projected patterns, and even more importantly, for use only with monochromatic, coherent, often collimated, laser sources. The cost and eye safety constraints of laser sources severely restrict DOE visualisation applications such as security holograms, and the 2D nature of the generated patterns limits virtual or augmented reality applications. To overcome these restrictions, this thesis targets the design and fabrication of wavelength selective 3D diffractive structures which can produce a perceived multiple view-angle “floating” 3D object behind the DOE substrate when illuminated by readily available and cheap white LED sources. In an initial approach we develop and experimentally validate a series of novel design algorithms for conventional optically “thin” DOE structures under incoherent, divergent illumination; first to project 2D patterns, then to create virtual 2D images and finally virtual 3D patterns. In a second stage, we leverage the capacities of optically “thick”, Bragg-like structures to introduce spectral selectivity (towards colour output patterns) and improve diffraction. Since the thin element approximation is invalid when designing optically thick 3D photonic structures we develop a particle swarm optimization algorithm based on a rigorous diffraction model to design highly innovative optically thick synthetic diffractive structures. The cost-effective fabrication of such proposed fully 3Dmicro- and nano-photonics structures is highly challenging when using current traditional lithographic techniques which are generally limited, in practice, to the fabrication of 2D or 2.5D structures. To this end, an advanced prototype massively parallelized two-photon polymerization (2PP) photoplotter for the fabrication of large area fully 3D photonic structures is currently being developed by the IMT Atlantique Optics Department. We present our contributions to the design and development of the critical, high uniformity illumination modules for the new prototype 2PP photoplotter. The research and development in this thesis contributes to the broadening of DOE applications to fields which are currently inaccessible. The developed design methods can also find applications in holographic display fields such as automotive augmented reality

La Wave Field Synthesis (WFS) est une technique qui vise à reconstruire les caractéristiques physiques d'un champ sonore en zone étendue, à partir d'un réseau de haut-parleurs. Le cadre défini pour la thèse est celui de la situation de concert de musique mixte, dans lequel un système WFS placé en nez de scène est utilisé pour synthétiser des instruments virtuels partageant l'espace acoustique de la scène avec des instrumentistes reels. La technique repose sur un ensemble d'approximations des principes théoriques sous-jacents qui n'assurent pas l'exactitude du champ reproduit. Par conséquent, le son direct rayonné par l'instrument virtuel WFS n'engendre pas un effet de salle conforme à celui qui serait engendré par un instrument réel. Le travail présenté consiste d'abord à analyser le champ effectivement rayonné par le banc de haut-parleurs, utilisant une méthode d'acoustique prédictive développée dans le cadre de la thèse. A partir de cette analyse, nous identifions la partie du champ rayonné par le banc de haut-parleurs dans la salle qui est naturellement cohérente avec celle d'un instrument réel. Nous proposons ensuite une méthode de compensation, permettant de rajouter la portion d'effet de salle manquante, basée sur une caractérisation préalable du système et l'injection d'énergie réverbérée via des sources WFS directives. Nous validons enfin la possibilité de contrôler l'effet de salle précoce en modifiant la directivité de rayonnement du banc WFS. Cette validation est basée sur des mesures réalisées in situ utilisant un microphone à haute résolution spatiale.

abstract: The objective of this work is to design a novel method for imaging targets and scenes which are not directly visible to the observer. The unique scattering properties of terahertz (THz) waves can turn most building surfaces into mirrors, thus allowing someone to see around corners and various occlusions. In the visible regime, most surfaces are very rough compared to the wavelength. As a result, the spatial coherency of reflected signals is lost, and the geometry of the objects where the light bounced on cannot be retrieved. Interestingly, the roughness of most surfaces is comparable to the wavelengths at lower frequencies (100 GHz – 10 THz) without significantly disturbing the wavefront of the scattered signals, behaving approximately as mirrors. Additionally, this electrically small roughness is beneficial because it can be used by the THz imaging system to locate the pose (location and orientation) of the mirror surfaces, thus enabling the reconstruction of both line-of-sight (LoS) and non-line-of-sight (NLoS) objects. Back-propagation imaging methods are modified to reconstruct the image of the 2-D scenario (range, cross-range). The reflected signal from the target is collected using a SAR (Synthetic Aperture Radar) set-up in a lab environment. This imaging technique is verified using both full-wave 3-D numerical analysis models and lab experiments. The novel imaging approach of non-line-of-sight-imaging could enable novel applications in rescue and surveillance missions, highly accurate localization methods, and improve channel estimation in mmWave and sub-mmWave wireless communication systems.
Dissertation/Thesis
Masters Thesis Electrical Engineering 2019

碩士
國立臺灣師範大學
光電科技研究所
104
This works mainly discusses how to optimize the system resolution in the digital holographic microscopy (DHM). We also try to enhance the system stability and simplify the experimental architecture by applying common-path setup. This research bases on reflection type DHM. The pixel resolution is improved by recording Fresnel hologram and up-sampling method. Then, the synthetic aperture (SA) technique is employed to enhance the spatial resolution in DHM system. In the experiments, the SA up-sampling technique gives better image resolution up to about 160 nm with phase accuracy about 6 nm by using visible light source. In addition, we produce a spiral phase filter by spatial light modulator (SLM) and place in the Fourier plane of common-path imaging system. The digital hologram can be recorded by separated the probe beam into object beam and reference beam. The quantitative complex amplitude information of object can thus be obtained by numerical reconstruction. In this common-path system, the stable architecture of interference system can avoid the influence from the external environment. So, it effectively increases system stability and simplifies the optical experimental setup. Finally, combing common-path spiral DHM and SA technique with 650 nm laser light source, the lateral resolution achieves about 280 nm with phase accuracy about 4 nm.

碩士
國立臺灣師範大學
光電科技研究所
105
This works mainly discusses how to optimize the system resolution in the digital holographic microscopy (DHM). We also try to enhance the system stability and simplify the experimental architecture by applying common-path setup. Finally, we set of non-coplanar angular-polarization multiplexing and coherence gating in synthetic aperture digital holographic microscopy system. This research bases on transmission type DHM. This work presents a common-path synthetic aperture digital holographic microscopy using spiral phase plate to improve phase stability and spatial resolution. The influence of lateral shift and defocus in spiral phase plane were analyzed at different illumination angles. In the experiments, the SA technique gives better image resolution up to about 200 nm with phase accuracy about 3.8 nm by using visible light source. In addition, we produce a non-coplanar angular-polarization multiplexing and coherence gating in synthetic aperture digital holographic microscopy system. We designed polarized and coherence gating, and with the use of spatial light modulator (SLM). We were able to record synthetic aperture digital images in single exposure conditions. In the experiments, the non-coplanar angular-polarization multiplexing and coherence gating in SA-DHM technique gives better image resolution up to about 1.5 times. If we record six hologram to do the space average. The system image resolution increased to 1.72 times.

碩士
國立中山大學
材料與光電科學學系研究所
103
In this study, we prepared several azobenzene composites for optical storage. The light-induced interconversion allows azobenzene composites to be used as rewritable and erasable optical storage materials. Four different materials were selected as the incorporating materials, which were used to combine with the azobenzene material (2-{[4-(dimethylamino)phenyl]diazenyl} benzoic acid, Methyl Red, MR). They were ((3-Aminopropyl)triethoxysilane, APTES, AP), (Bis(3-aminopropyl)amine, BAA), (Polypropylenimine tetramine dendrimer, PPI) and ({Trimethylolpropane tris[poly(propylene glycol), amine terminated] ether}, TPGA). These azobenzene composites were formed by ionic bonding, which reduces the oppertunity of the phase separation and enhances the thermal stability for long term preservation. The diffraction efficiency of the composites MR/AP, MR/BAA, MR/PPI, MR/TPGA, were 19%, 17%, 16% and 18%. Atomic force microscopy revealed that surface variation of these composites was 768,758, 1467 and 729 nm, respectively, while N&;K results show that the sample thickness before holographic recording was 1422nm、1047nm、2148nm、762nm, respectively.

碩士
國立中山大學
材料與光電科學學系研究所
107
In this study, it will be divided into two parts of material synthesis and optical characterizations. The first part is the synthesis of materials. The monomers Azo-hexyl-Br, Azo-Pyridine-2NO2 and Azo-Pyridine-2NH2 on azobenzene containing pyridine are synthesized respectively. Further, the Azo-Pyridine-Phenol Bz and Azo-Pyridine-Bisphenol Bz containing polybenzoxazine were synthesized. The monomers and polymers characterized by Fourier Transform Infrared spectrometer (FT-IR) and Nuclear Magnetic Resonance spectrometer (NMR). For getting completed structural identification and thermal properties analysis, these two polymers characterized by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analyzer (TGA); the second part is optical application. The synthesized polymers are made into an optical sample to a holographic interference experiment. Before the experiment, it is necessary to understand the absorption band of the monomer preference, so the monomers Azo-hexyl-Br, Azo-Pyridine-2NO2 and Azo-Pyridine-2NH2 are at the wavelength of absorption light. The 365 nm ultraviolet light was irradiated for several minutes, and the UV-vis was measured separately to understand the degree of light absorption of the three structures. The initial monomer Azo-hexyl-Br had good performance on light absorption. It can be known that the structure has a cis-trans transition of azobenzene, and since the comparative spectrum shows that pyridine has a light absorption reaction for ultraviolet light. Therefore, this experiment uses a green light laser of 532 nm as a writing beam, and also uses a red light laser of 633 nm as a reading beam.

碩士
國立中山大學
材料與光電科學學系研究所
106
Azobenzene molecules exhibit numerous photoresponsive features and the irradia- tion of azobenzenes with polarized light results in a fast and efficient photoselective isom- erization,accompanied by a chromophore motion and alignment.An azo chromophore (4- Aminoazobenzene, AAB) was selected as the photosensitive monomer.The functional epoxy used was ((3-Glycidyloxypropyl)trimethoxysilane, GPTMS).We have used ring opening reaction of GPTMS,AAB was employed instead of the component providing for the ring opening,whereas AAB become covalently bonded to GPTMS. In this study, We found that the reaction time of the Sol-Gel process played an key role to influence cross-linking degree of the GPTMS. Meanwhile, the reaction tempera- ture might change the degree of bonding between AAB and GPTMS (AG).The main goal is to achieve the efficient formation of (surface relief gratings, SRGs) and efficient Dif- fraction Efficiency. We found the optimal parameters to produce azobenzene holographic materials with efficient formation of SRGs and efficient Diffraction Efficiency.The Diffraction Effi- ciency of the composites AG was 30.87% and it could be achieved in 15 minutes. From the data measurement by Atom Force microscopy (AFM), it revealed the SRGs depth of AG were 40.8 nm.

博士
國立交通大學
材料科學與工程系
87
Three types of PR polymers are prepared in this thesis. The first type polymers are prepared by doping the nonlinear optical host polymer with charge transport agents. The in-situ optical nonlinearity during poling and thermal stability is discussed. Then, trap characteristics of polymeric PR materials are studied for the first time using a thermally stimulated current (TSC) spectrometer. Both the trap depth and the trap density distribution in energy are derived from the TSC spectra. The effect of each component and the main chain structure of the PR polymer system on the trap behaviors are investigated. Since the nonlinear optical polymer and a charge generation material (CGM) exhibit different visible light absorption spectrum, we find that the wavelength of the writing and reading beams also shows a tremendous effect on the photorefractivity. It reveals that choosing appropriate writing and reading laser beams can speed up the response time of PR polymeric materials. To prevent crystallization, the second and the third types of polymers prepared in this thesis are fully functionalized PR polymers where both the charge transporting moieties and NLO moieties are chemically bonded on the main chain. We try to extend the storage lifetime, speed up the response time and increase the storage density of the medium in this chapter. TNF is added into the film as the sensitizer. The images are stored, erased, and overwritten in the PR polymers to investigated the erasure and update capability of the film. The influences of relative component concentrations, the applied electric field, and sensitizers on the PR response time and the diffraction efficiency are also studied. Using the angle multiplexing technique, many pages of data can be stored on the same spot of the medium either by changing the angle between the writing beams or by rotating the medium to different angles for each recording. Thus, specific pages can be accessed by selecting the corresponding angle of the reading beam. By adjusting the polymer/curing agent ratio and choosing a curing agent with proper chain length, a crosslink polymeric network with appropriate cross-linked density is synthesized to slow down the randomization of the oriented chromophores. To achieve large diffraction efficiency and fast response, the third type of PR polymer is prepared from one single active component (dual functional chromophore) to elevate the concentration of each functionality as high as possible. The relationships between the nonlinear optical and the holographic properties are studied. The diffraction efficiencies of the PR polymers are elevated in two ways. First, dual functional chromophores are used to maximize the concentration of each functionality. Second, the second-order optical susceptibility is promoted by extending the conjugation length with an additional electron donating group and an additional electron withdrawing group and/or introducing the five-membered heterocyclic ring onto the chromophore molecules. The influence of the electron acceptor of the chromophores on the PR characteristics is investigated. The resolution of the stored images in the PR polymers and their update capability for data storage are also evaluated.

碩士
國立中山大學
材料與光電科學學系研究所
107
The laboratory prepares azobenzene holographic materials with repeated reading and writing and fast writing, which can be used in applications such as optical storage and optical display.Due to the previous lab team，An azo chromophore ([2-{[4-(dimethylamino)phenyl]diazenyl}benzoic acid]，MR) was selected as the photosensitive monomer. The functional epoxy used was (Bis(3-aminopropyl)amine, BAA) ，whereas MR become ionic bonded to BAA. Using the characteristics of small molecules, the maximum diffraction efficiency is 17% in 1 minute, and the (surface relief gratings, SRGs) is as high as 758 nm, which is a very excellent performance in the field of holographic storage materials. The disadvantage is that the stability is not good enough, and the holographic storage is easily deteriorated. In this study, Found to increase material stability .the addition of biphenyl in the holographic storage material is used to change the amount and thickness of the addition to find the best parameters for the holographic storage.

碩士
國立中山大學
材料與光電科學學系研究所
106
In this study, we prepared several azobenzene composites for optical storage. The light-induced interconversion allows azobenzene composites to be used as rewritable and erasable optical storage materials. 4-Aminoazobenzene (AAB) was selected as the pho-tochromic monomer, and two kinds of substrates with different low molecular weights were used to form composites by means of covalent bonds. The substrates used were (1,3,5-Benzenetricarbonyl trichloride, BTC), (Benzoyl chloride, BC). The synthesis of materials AT and AAB/BC was determined by nuclear magnetic resonance (NMR), and the formation of surface relief gratings was observed by AFM. According to L.M. Goldenberg team8, we change the parameters and make the ma-terial AT into a thin film, which diffraction efficiency reached 42.9% at 20 minutes, and η=57.21% at 128 minutes. Due to the low molecular weight of the material AAB/BC, the film-forming properties are poor and further optical measurements cannot be made. The high diffraction efficiency (57.21%) of the material AT can be applied not only to the optical storage element, but also applicable to the communication element. This material is extremely excellent in optics .