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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Some properties of photorefractive spatial solitons

Liu, Yafang January 2002 (has links)
No description available.
2

Observation of phase-dependent interactions of bright photovoltaic spatial solitons and theoretical studies of photorefractive hologram writing with high modulation depth in photovoltaic media. / 摻鐵鈮酸鋰晶體中相位相關的亮光生伏打空間孤子的相互作用的觀察及光生伏打媒介中高調制深度下所寫的光折變全息圖的理論研究 / Observation of phase-dependent interactions of bright photovoltaic spatial solitons and theoretical studies of photorefractive hologram writing with high modulation depth in photovoltaic media. / Shan tie ni suan li jing ti zhong xiang wei xiang guan de liang guang sheng fu da kong jian gu zi de xiang hu zuo yong de guan cha ji guang sheng fu da mei jie zhong gao diao zhi shen du xia suo xie de guang zhe bian quan xi tu de li lun yan jiu

January 2007 (has links)
Chan Tak Shun = 摻鐵鈮酸鋰晶體中相位相關的亮光生伏打空間孤子的相互作用的觀察及光生伏打媒介中高調制深度下所寫的光折變全息圖的理論研究 / 陳德信. / Thesis submitted in: July 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 115-116). / Abstracts in English and Chinese. / Chan Tak Shun = Shan tie ni suan li jing ti zhong xiang wei xiang guan de liang guang sheng fu da kong jian gu zi de xiang hu zuo yong de guan cha ji guang sheng fu da mei jie zhong gao diao zhi shen du xia suo xie de guang zhe bian quan xi tu de li lun yan jiu / Chen Dexin. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Chapter Chapter 1 --- Introduction --- p.1 / References --- p.9 / Chapter Chapter 2 --- Background --- p.10 / Chapter 2.1 --- Space-Charge Field and Band Transport Model --- p.10 / Chapter 2.2 --- Photorefractive Effect and Nonlinear Wave Equation --- p.24 / Chapter 2.3 --- Two-Wave Mixing and Diffraction of Light Incident onto an Index Grating --- p.34 / Chapter 2.4 --- Photorefractive Spatial Solitons --- p.48 / References --- p.60 / Chapter Chapter 3 --- Relevance of interpretation of experimental results of interactions of optical spatial solitons and interaction geometry --- p.62 / Chapter 3.1 --- Introduction --- p.62 / Chapter 3.2 --- Theoretical Model --- p.63 / Chapter 3.3 --- Results and Discussion --- p.65 / Chapter 3.4 --- Conclusions --- p.71 / References --- p.72 / Chapter Chapter 4 --- Experimental investigation of phase-dependent interactions of photovoltaic bright spatial solitons in photorefractive Fe:LiNb03 --- p.75 / Chapter 4.1 --- Introduction --- p.75 / Chapter 4.2 --- Theoretical Background --- p.76 / Chapter 4.3 --- Experiment --- p.83 / Chapter 4.4 --- Results and Discussion --- p.86 / Chapter 4.5 --- Conclusions --- p.90 / References --- p.91 / Chapter Chapter 5 --- Photorefractive hologram writing with high modulation depth in photovoltaic media under different boundary conditions --- p.94 / Chapter 5.1 --- Introduction --- p.94 / Chapter 5.2 --- Theoretical Model and Method --- p.97 / Chapter 5.3 --- Results and Discussion --- p.99 / Chapter 5.4 --- Conclusions --- p.114 / References --- p.115 / Chapter Chapter 6 --- Conclusions and future outlook --- p.117
3

Photorefractive effects in optical fibers grating fabrication and characterization

Chen, Junfu 05 1900 (has links)
No description available.
4

Refractive surgery with the ArF excimer laser (Photorefractive keratectomy) : surgical technique, wound healing and refractive results /

Hamberg-Nyström, Heléne, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.
5

Design, synthesis and physical studies of novel organic photonic materials /

Wang, Qing, January 2000 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry. / Includes bibliographical references. Also available on the Internet.
6

Analysis and optimization for volume holographic recording

Momtahan, Omid. January 2006 (has links)
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Smith, Glenn, Committee Member ; Trebino, Rick, Committee Member ; Adibi, Ali, Committee Chair ; Gaylord, Thomas, Committee Member ; Buck, John, Committee Member.
7

Visible and Near Infrared Sensitive Photorefractive Polymers for Holographic Display Applications

Eralp, Muhsin January 2007 (has links)
This work presents recent advances in photorefractive polymer composites towards improved efficiency, speed, persistence of holograms and sensitivity at both visible and near infrared wavelengths. Besides the pure performance characteristics, a thin-device approach is presented to reduce operating voltage of these devices to practical levels and these materials are analyzed in both reflection and transmission geometries.The thin device operating at 1.3kV holds erasable, Bragg holograms with 80% efficiency in addition to its video-rate response time. The transition of hologram state from 'thick' to 'thin' is analyzed in detail. On the near IR portion of spectrum, new photorefractive polymer composites have been developed that enable high performance operation at 845nm and 975nm. Utilizing our novel photorefractive materials we demonstrate large diffraction efficiency in four-wave mixing experiments and video-rate response times. A major step towards achieving submillisecond response times is obtained through recording photorefractive gratings with individual nanosecond pulses at 532nm. At 4 mJ/cm2 illumination, a maximum diffraction efficiency of 56% has been obtained with a build-up time of only 300 microseconds (t1). This fast response enables applications in optical processing requiring frame rates of 100Hz or more. Due to the short duration of the writing pulses, the recording is insensitive to vibrations. Combining molecules that have different frontier orbital energies in a copolymer system and utilizing thermal fixing approach has led to long grating lifetimes of more than several hours. Later, in this dissertation, two low-glass-transition photorefractive polymer composites are investigated in reflection geometry. 60% is diffraction efficiency is observed in 105 micron thick devices of a PVK based composite. The reflection holograms are more sensitive to reading angle and slight birefringence due to the poling of chromophores has proven to cause a Bragg mismatch.
8

Improving Sensitivity of Photorefractive Polymer Composites for Holographic Display Applications

Christenson, Cory January 2011 (has links)
This work presents recent progress in the area of organic photorefractive polymer composites. These materials have been previously shown to be a suitable medium for dynamic holographic displays, with multiple colors and single frame writing times on the order of seconds. However, these materials still require large electric fields and high intensity lasers to function effectively. Recent advancements in improving these areas are discussed, including a review of the history and state-of-the-art in photorefractive polymer composites.The addition of electron traps via low loading of the electron-transporting molecule Alq3 is shown to dramatically improve the diffraction efficiency and reduce the required field. The grating formation also proceeds faster by more than one order of magnitude, leading to an increase in sensitivity by a factor of 3. The dynamics of these materials also show evidence of competing gratings indicative of bipolar charge transport and trapping.The addition of an amorphous polycarbonate (APC) buffer layer is reported to have a similar effect on the steady-state diffraction efficiency, and the further doping with a fullerene derivative (PCBM) allows a 3x increase in the efficiency in the reflection geometry, which is normally poor due to the small grating spacing. These composites reveal the fundamental limits of the reflection geometry, based on the physics of high frequency gratings. A reversal in the direction and increase in the magnitude of the two-beam coupling energy transfer is also observed.The use of interdigitated coplanar electrodes, instead of the standard uniform electrodes in a parallel-plate geometry, is shown to result in large diffraction efficiency with symmetric writing beams due to the increased projection field. The efficiency is similar to that achieved in the standard samples with large slant angles and much better than those geometries typically used in applications, with the benefit that the writing beams do not have to be slanted with respect to the sample normal. Different electrode widths are examined and the trade-offs discussed. This device makes beam injection simpler and allows one to bring the benefits of highly slanted geometries, common to small area setups, to the large-area applications.
9

Effects of a laser beam on another laser beam in a photorefractive crystal. / 一激光束對在光折變晶體中之另一激光束的影響 / Effects of a laser beam on another laser beam in a photorefractive crystal. / Yi ji guang shu dui zai guang zhe bian jing ti zhong zhi ling yi ji guang shu de ying xiang

January 2000 (has links)
by Lee, Kai Kwong Dennis = 一激光束對在光折變晶體中之另一激光束的影響 / 李啓光. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 106-109). / Text in English; abstracts in English and Chinese. / by Lee, Kai Kwong Dennis = Yi ji guang shu dui zai guang zhe bian jing ti zhong zhi ling yi ji guang shu de ying xiang / Li Qiguang. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Content --- p.iv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Theory --- p.4 / Chapter 2.1 --- Two-wave Coupling --- p.4 / Chapter 2.2 --- Four-wave Mixing --- p.10 / Chapter 2.3 --- Fanning --- p.13 / Chapter 2.4 --- Phase-conjugation --- p.16 / Chapter 2.5 --- Spatial Solitons --- p.19 / Chapter Chapter 3 --- "Experiments,Results and Discussion" --- p.26 / Chapter 3.1 --- Measurements of Optically Induced Refractive Index Change --- p.26 / Chapter 3.2 --- Optical Control Experiments --- p.65 / Chapter 3.3 --- Soliton Experiments --- p.80 / Chapter Chapter 4 --- Concluding Remarks and Suggested Further Studies --- p.99 / References --- p.105
10

Two-wave coupling and time dependent absorption coefficient of photorefractive crystal =: 光折變晶体中之二波耦合與時間相關之吸收系數. / 光折變晶体中之二波耦合與時間相關之吸收系數 / Two-wave coupling and time dependent absorption coefficient of photorefractive crystal =: Guang zhe bian jing ti zhong zhi er bo ou he yu shi jian xian guan zhi xi shou xi shu. / Guang zhe bian jing ti zhong zhi er bo ou he yu shi jian xian guan zhi xi shou xi shu

January 1995 (has links)
by Wing-keung Mak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 51-53). / by Wing-keung Mak. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Content --- p.iii / Chapter Chapter One --- Introduction --- p.1 / Chapter Chapter Two --- Theory / Chapter 2.1 --- Theory of Two-wave Coupling --- p.3 / Chapter 2.2 --- Theory of Fanning --- p.8 / Chapter 2.3 --- Theory of Time Dependent Absorption Coefficients of Photorefractive Crystals --- p.10 / Chapter Chapter Three --- Photorefractive Fabry-Perot Etalon / Chapter 3.1 --- Theory and Numerical Computation --- p.12 / Chapter 3.2 --- Summary of Crystal Parameters --- p.15 / Chapter 3.3 --- Experimental Studies of Interference Patterns --- p.16 / Chapter 3.4 --- Intensity Dependence of Fabry-Perot Etalon Interference Patterns --- p.25 / Chapter 3.5 --- Fanning --- p.29 / Chapter 3.6 --- Bright Spots on Interference Patterns --- p.31 / Chapter Chapter Four --- Time Dependent Absorption Coefficients of Photorefractive Crystals / Chapter 4.1 --- Experiments Using Laser Light --- p.34 / Chapter 4.2 --- Experiments Using White Light --- p.44 / Chapter Chapter Five --- Conclusion and Future Outlook --- p.49 / References --- p.51

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