Guo Bin = 光折變摻銅鉀鈉鈮酸鍶鋇和摻鐵鈮酸鋰晶體中的二波耦合及摻鐵鈮酸鋰晶體中的亮光伏空間孤子 / 郭斌. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Guo Bin = Guang zhe bian shan tong jia na ni suan si bei he shan tie ni suan li jing ti zhong de er bo ou he ji shan tie ni suan li jing ti zhong de liang guang fu kong jian gu zi / Guo Bin. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Chapter Chapter 1 --- Introduction --- p.1 / References --- p.6 / Chapter Chapter 2 --- Background --- p.7 / Chapter 2.1 --- Photorefractive Effect Based on Band Transport Model --- p.7 / Chapter 2.2 --- Photovoltaic Effect --- p.15 / Chapter 2.3 --- Surface Charge Recombination in Fe:LiNb〇3 Crystals --- p.17 / References --- p.19 / Chapter Chapter 3 --- Noise of Two-Wave Mixing in Cu:KNSBN Crystal --- p.20 / Chapter 3.1 --- Introduction --- p.20 / Chapter 3.2 --- Experimental Setup --- p.22 / Chapter 3.3 --- Results and Discussion --- p.23 / Chapter 3.4 --- Conclusion --- p.29 / References --- p.30 / Chapter Chapter 4 --- Bright Photovoltaic Spatial Soliton in Fe:LiNb03 Crystals / Chapter 4.1 --- Introduction --- p.32 / Chapter 4.2 --- Theory --- p.33 / Chapter 4.3 --- Experimental Setup --- p.36 / Chapter 4.4 --- Results and Discussion --- p.39 / Chapter 4.5 --- Conclusion --- p.58 / References --- p.59 / Chapter Chapter 5 --- Two-Wave Mixing of Narrow Laser Beams in a Fe:LiNbO3 Crystal --- p.60 / Chapter 5.1 --- Introduction --- p.60 / Chapter 5.2 --- Theory of Two-Wave Mixing --- p.62 / Chapter 5.3 --- A Simplified Analysis of Two-Wave Mixing of Narrow Beams --- p.66 / Chapter 5.4 --- Experimental Setup --- p.70 / Chapter 5.5 --- Results and Discussion --- p.71 / Chapter 5.6 --- Conclusion --- p.86 / References --- p.87 / Chapter Chapter 6 --- Two-Wave Mixing of Narrow Laser Beams with an Incoherent Background Beam --- p.89 / Chapter 6.1 --- Theory --- p.89 / Chapter 6.2 --- Experimental Setup --- p.93 / Chapter 6.3 --- Results and Discussion --- p.94 / Chapter 6.4 --- Conclusion --- p.105 / References --- p.106 / Chapter Chapter 7 --- Conclusion and Future Outlook --- p.107

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 15, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Ping Yu. Vita. Includes bibliographical references.

No description available.

Thesis (Ph.D.)--Tufts University, 1995. / Adviser: M. Cronin-Golomb. Submitted to the Dept. of Electrical Engineering. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Lobjectif de cette thèse était de concevoir et développer un dispositif expérimental réalisant des mesures dans la gamme micrométrique, qui soit compact, transportable et le plus stable possible pour la réalisation de mesures in-situ. Ce projet a donc contribué à la conception et à la réalisation dun dispositif interférométrique de shearographie qui constituera une base pour de futurs développements. Un interféromètre original de shearographie à chemins optiques quasi-communs et utilisant la technique du décalage de phase temporel a été présenté dans ce travail. Lélément clef du montage expérimental de shearographie est le dispositif de cisaillement (« shearing device », en anglais) : il sagit dun prisme qui sépare les états de polarisation TE et TM grâce à une couche mince polarisante et une fine lame de verre qui lui est accolée. Cet élément de cisaillement ainsi que lutilisation dune caméra CMOS et dune cellule à cristaux liquide pour modulateur de phase, ont permis la réalisation dun interféromètre compact, en ligne, relativement bon marché et à chemins optiques quasi-communs, lui conférant ainsi une grande stabilité par rapport aux perturbations extérieures. De plus, la sensibilité de cet interféromètre peut être ajustée pour différentes applications en modifiant la distance de cisaillement, par exemple en utilisant une lame de verre dépaisseur différente accolée au prisme séparateur de polarisation. Des logiciels pour lacquisition et le traitement des images ont également été développés afin de rendre le système simple dutilisation et convivial. Lefficacité de cet interféromètre de shearographie a été prouvée dans le domaine mécanique et une application originale a été développée dans le domaine de la biophotonique.

Methods for analysis and optimization of volume holographic recording are presented for two main groups of applications. In the first group of applications (mainly storage systems), the designs and the techniques of volume holography are well known and the main optimization effort is finding the proper material to store the holograms. One of the results of this research is complete global optimization of dynamic range and sensitivity in two-center recording that is the best technique for persistent rewritable storage. For this purpose, a complete theoretical analysis as well as experimental demonstration is presented. Also, other effects and processes such as electron tunneling and recording at high temperature are considered for possible improvement of the dynamic range of the material. For the second group of applications (mainly holographic optical elements), the focus of this research is on analysis and optimization of the design of the volume holograms in contrast to material optimization. A new method (multi-grating method) is developed for the analysis of an arbitrary hologram that is based on the representation of the hologram as the superposition of several plane wave gratings. Based on this method, a new class of optical devices that integrates the functionalities of different optical elements into a simple volume hologram is introduced and analyzed. As a result, very compact, low cost, and easy to use devices such as portable spectrometers can be made with particular applications in biological and environmental sensing.

Generally, nonlinear optics studies investigate optically-induced changes in refraction or absorption, and their application to spectroscopy or device fabrication. The photorefractive effect is a nonlinear optical effect that occurs in solids, where transport of an optically-induced free-carrier population results in an internal space-charge field, which produces an index change via the linear electrooptic effect. The photorefractive effect has been widely studied for a variety of materials and device applications, mainly because it allows large index changes to be generated with laser beams having only a few milliwatts of average power.Compound semiconductors are important photorefractive materials because they offer a near-infrared optical response, and because their carrier transport properties allow the index change to be generated quickly and efficiently. While many researchers have attempted to measure the fundamental temporal dynamics of the photorefractive effect in semiconductors using continuous-wave, nanosecond- and picosecond-pulsed laser beams, these investigations have been unsuccessful. However, studies with this goal are of clear relevance because they provide information about the fundamental physical processes that produce this effect, as well as the material's speed and efficiency limitations for device applications.In this dissertation, for the first time, we time-resolve the temporal dynamics of the photorefractive nonlinearities in two zincblende semiconductors, semi-insulating GaAs and undoped CdTe. While CdTe offers a lattice-match to the infrared material HgxCd1-xTe, semi-insulating GaAs has been widely used in optoelectronic and high-speed electronic applications. We use a novel transient-grating experimental method that allows picosecond temporal resolution and high sensitivity. Our results provide a clear and detailed picture of the picosecond photorefractive response of both materials, showing nonlinearities due to hot-carrier transport and the Dember space-charge field, and a long-lived nonlinearity that is due to the EL2 midgap species in GaAs. We numerically model our experimental results using a general set of equations that describe nonlinear diffraction and carrier transport, and obtain excellent agreement with the experimental results in both materials, for a wide variety of experimental conditions.

This work presents recent advances in the development of infra-red sensitive photorefractive polymers, and updateable near real-time holographic 3D displays based on photorefractive polymers. Theoretical and experimental techniques used for design, fabrication and characterization of photorefractive polymers are outlined. Materials development and technical advances that made possible the use of photorefractive polymers for infra-red free-space optical communications, and 3D holographic displays are presented.Photorefractive polymers are dynamic holographic materials that allow recording of highly efficient reversible holograms. The longest operation wavelength for a photorefractive polymer before this study has been 950nm, far shorter than 1550nm, the wavelength of choice for optical communications and medical imaging. The polymers shown here were sensitized using two-photon absorption, a third order nonlinear effect, beyond the linear absorption spectrum of organic dyes, and reach 40% diffraction efficiency with a 35ms response time at this wavelength. As a consequence of two-photon absorption sensitization they exhibit non-destructive readout, which is an important advantage for applications that require high signal-to-noise ratios.Holographic 3D displays provide highly realistic images without the need for special eyewear, making them valuable tools for applications that require "situational awareness" such as medical, industrial and military imaging. Current commercially available holographic 3D displays employ photopolymers that lack image updating capability, resulting in their restricted use and high cost per 3D image. The holographic 3D display shown here employs photorefractive polymers with nearly 100% diffraction efficiency and fast writing time, hours of image persistence, rapid erasure and large area, a combination of properties that has not been shown before. The 3D display is based on stereography and utilizes world's largest photorefractive devices (4x4 inch in size). It can be recorded within a few minutes, viewed for several hours without the need for refreshing and can be completely erased and updated with new images when desired, thusly comprising the first updateable holographic 3D display with memory, suitable for practical use.

An optical computer which performs the classification of an input object pattern into one of two learned classes is designed and demonstrated. The classifier is an optical implementation of a neural network model of computation featuring learning, self-organization, and decision-making competition. Neural computation is discussed including models for learning networks and motivation for optical implementation. A discussion of photorefractive crystal holographic storage and adaptation is presented followed by experimental results of writing and erasing gratings in several different crystals. The optical network features a photorefractive crystal to store holographic interconnection weights and an opto-electronic circuit to provide a means of competitive decision making and feedback. Results of the optical learning network and its operation as an associative memory are followed by extensions of the architecture to allow improved performance and greater flexibility.