[PDF] Photorefractive Polymer Composites For Holographic Optical Coherence Imaging eBook

Author : Pierre-Alexandre Blanche
Publisher : Springer
Page : 325 pages
File Size : 15,20 MB
Release : 2016-06-10
Category : Technology & Engineering
ISBN : 3319293346

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This book provides comprehensive, state-of-the art coverage of photorefractive organic compounds, a class of material with the ability to change their index of refraction upon illumination. The change is both dynamic and reversible. Dynamic because no external processing is required for the index modulation to be revealed, and reversible because the index change can be modified or suppressed by altering the illumination pattern. These properties make photorefractive materials very attractive candidates for many applications such as image restoration, correlation, beam conjugation, non-destructive testing, data storage, imaging through scattering media, holographic imaging and display. The field of photorefractive organic material is also closely related to organic photovoltaic and light emitting diode (OLED), which makes new discoveries in one field applicable to others.

Author : Dave West
Publisher : CRC Press
Page : 150 pages
File Size : 38,90 MB
Release : 2004-11-29
Category : Science
ISBN : 0203506618

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Photorefractive polymer composites are an unusually sensitive class of photopolymers. Physics of Photorefraction in Polymers describes our current understanding of the physical processes that produce a photorefractive effect in key composite materials. Topics as diverse as charge generation, dispersive charge transport, charge compensation and trap

Author : Peter Bamfield
Publisher : Royal Society of Chemistry
Page : 812 pages
File Size : 13,46 MB
Release : 2018-08-22
Category : Science
ISBN : 1788015037

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Chromic or colour related phenomena are produced in response to a chemical or physical stimulus. This new edition will update the information on all those areas where chemicals or materials interact with light to produce colour, a colour change, or luminescence especially in the imaging, analysis, lighting and display areas. The book has been restructured to show greater emphasis on applications where 'coloured' compounds are used to transfer energy or manipulate light in some way therefore reducing the details on classical dyes and pigments. In the past eight years, since the previous edition, there has been a remarkable increase in the number of papers and reviews being produced reflecting the growth of interest in this area. This ongoing research interest is matched by a large number of new technological applications gaining commercial value covering e.g. biomedical areas, energy, data storage, physical colour, bio-inspired materials and photonics. This book appeals to industrial chemists, professionals, postgraduates and as high level recommended reading for colour technology courses.

Author : Jaime Frejlich
Publisher : John Wiley & Sons
Page : 336 pages
File Size : 31,54 MB
Release : 2007-01-29
Category : Technology & Engineering
ISBN : 0470089059

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Photorefractive Materials presents an overview of the basic features and properties of photorefractive materials, covering a wide array of related topics. It provides a coherent approach suitable for introductory and advanced students seeking to learn or review the fundamentals, as well as senior researchers who need a reference while investigating more specialized areas.

Author : Cory Christenson
Publisher :
Page : 332 pages
File Size : 32,82 MB
Release : 2011
Category :
ISBN :

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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.

Author : Muhsin Eralp
Publisher :
Page : 332 pages
File Size : 47,6 MB
Release : 2007
Category :
ISBN :

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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.

Author : Johannes Karl Fink
Publisher : William Andrew
Page : 442 pages
File Size : 48,24 MB
Release : 2014-07-04
Category : Technology & Engineering
ISBN : 0323311431

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Approaching the material from a chemistry and engineering perspective, High Performance Polymers presents the most reliable and current data available about state-of-the-art polymerization, fabrication, and application methods of high performance industrial polymers. Chapters are arranged according to the chemical constitution of the individual classes, beginning with main chain carbon-carbon polymers and leading to ether-containing, sulfur-containing, and so on. Each chapter follows an easily readable template, provides a brief overview and history of the polymer, and continues on to such sub-topics as monomers; polymerization and fabrication; properties; fabrication methods; special additives; applications; suppliers and commercial grades; safety; and environmental impact and recycling. High Performance Polymers brings a wealth of up-to-date, high performance polymer data to you library, in a format that allows for either a fast fact-check or more detailed study. In this new edition the data has been fully updated to reflect all developments since 2008, particularly in the topics of monomers, synthesis of polymers, special polymer types, and fields of application. Presents the state-of-the-art polymerization, fabrication and application methods of high performance industrial polymers Provides fundamental information for practicing engineers working in industries that develop advanced applications (including electronics, automotive and medical) Discusses environmental impact and recycling of polymers