Download or read book On Improving the Optical Quality of Colloidal Photonic Crystals microform written by Mathieu Allard and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2004 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work advances the understanding of the impact of lattice disorder on the optical properties of colloidal photonic crystals. It also demonstrates and quantifies improvements in the structural and optical quality of the crystals through refinements of the fabrication techniques. Arrays of colloidal particles were grown on substrates covered with holographic relief gratings realized in photoresist films. When the grating pitch was commensurate with the particle size, a uniform lattice orientation was imposed in the crystals. The enhancement in crystal order was visible for thicknesses as large as 40 layers. The impact of lattice disorder on the optical properties of colloidal photonic crystals was investigated numerically. The greatest impact on the optical properties came from size non-uniformity of colloidal particles. A novel algorithm, based on simulated annealing, was used to generate densely packed arrays of spheres with a given size distribution. When the size standard deviation was larger than 3%, a transition from ordered to random-packed arrangements was observed, along with large and sudden changes in optical properties, in the form of increased scattering and reduced contrast associated with the 111 stopband in transmittance spectra. The abruptness of this transition increased with decreasing index contrast. The numerical results agreed well with experimental results. The enhancement of long-range order was further demonstrated and quantified by optical techniques. The diffraction patterns produced when a collimated laser beam illuminated colloidal crystals were shown to be capable of revealing whether the crystals were mono- or poly-crystalline. Quantitative information about internal ordering was also extracted from diffraction spectra: the photon mean free path in the crystal was estimated to be in the range of 3 to 58 lattice constants, depending on the crystal growth conditions.
Download or read book Photonic Crystals written by Qihuang Gong and published by CRC Press. This book was released on 2014-02-06 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a broad overview of photonic crystals and, as the title suggests, covers their principles and applications. It is written from a physics point of view with an emphasis on materials science. Equations are well explained and often completely avoided to increase the readability of the book. The book is divided into eight chapters, starting with a brief introduction. The second chapter deals with different dimensionalities of the photonic crystals and their properties. The third chapter is very interestingly written and provides a survey of the various synthesis methods used for production of photonic crystals, including chemical routes, lithography, and self-assembly of colloidal photonic crystals. Chapters 4–8 constitute the bulk of the book and provide examples of applications of these photonic crystals. Chapter 4 offers a good explanation of optical switching. Bandgap and defect mode switching are also brought into focus along with many other mechanisms—14 different switching mechanisms in all, including thermal, electro, and magneto switching. Frequency tuning of photonic crystal filters with special attention to nanosize photonic crystals is illustrated, providing a direct perspective on applications of these materials in integrated photonic circuits. The transition from chapter 5 to 6 dealing with photonic crystal lasers is smooth, especially after a clear description of frequency tuning. Here, one- to three-dimensional photonic lasers are explained along with laser oscillations produced by a variety of microcavity methods. Metallodielectric and liquid-crystal photonic lasers are equally well illustrated. Chapter 7 introduces logic devices based on photonic crystals. This chapter clearly explains, with the help of simple illustrations, how to obtain AND, OR, and XOR logic gates. Chapter 8 concludes the book by presenting possible applications, including gas, chemical, fluid, and cell sensing; their workings are very well described from a fundamental point of view. The diagrams and illustrations are appropriate and eye catching. There are ample references; thus readers are able to find more detailed information to satisfy their curiosity if the book does not suffice. Even though the introduction provides basics of these photonic crystals, I do get the impression that the bigger picture is missing. A nonexpert may not understand the direct application of such materials right from the beginning of the book. A flowchart or a diagram of these photonic crystals, illustrating applications in daily life at the beginning of the book, could attract a broader readership. In this regard, I believe that this book is most adapted to physicists with a materials science background or vice versa. However, one should take into consideration that the principles of photonic crystals cannot be explained without physics, and therefore the quality of this book remains intact and could very well serve as a textbook for future physicists.
Download or read book Intrinsic and Extrinsic Defects in Colloidal Photonic Crystal Films written by Evangellos William Vekris and published by . This book was released on 2007 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photonic crystals (PC's) are a new class of engineered material that is structurally periodic on the scale of optical wavelengths. One promising form of photonic crystal is the self-assembled colloidal crystal film, which consist of a close-packed lattice of colloidal spheres and can be grown inexpensively from a colloidal dispersion. This crystal can serve as a template for the infiltration of a material of higher refractive index, such as silicon, to create a material possessing a complete photonic bandgap (PBG). However, the self-assembled nature of colloidal crystal films allows the formation of intrinsic defects. Such defects, disruptions in the lattice periodicity, can be expected to influence the optical properties of this photonic material. Here, various intrinsically-formed defects are structurally analyzed by microscopy, and their optical properties are then individually measured through careful spatially-resolved optical spectroscopy. Point, line, and volume defects are shown to contribute to incoherent scattering, in good agreement with numerical simulation. In all cases, the influence of such defects on the fundamental stop-band is negligible, while influences on the "higher-band" region of the bandstructure and the PBG are shown to be significant. Stacking faults, variations in the stacking of close-packed crystalline planes, are also analysed. It is shown that different stacking sequences give rise to unique optical spectra, which are shown to differ in the higher-band region of the bandstructure, while leaving the fundamental stopgap unaffected. Additionally, stacking faults are shown to be caused by the incorporation of differently-sized impurity spheres in the lattice, a hard- sphere type mechanism analogous to atomic systems. A fabrication method for extrinsic defects, those which are deliberately introduced to create a designed photonic functionality, and which combines top-down photolithographic patterning with bottom-up self-assembly, is presented. Defects created using this technique can potentially serve as optical waveguides in silicon inverse colloidal photonic crystals, with applications in optical telecommunications or optical computing. Through better understanding of the structure, optical properties, and formation mechanisms of colloidal crystal defects, the quality of self-assembled photonic crystal films can be improved, resulting in more homogeneous optical properties and allowing the full-potential of colloidal photonic crystals to be realized.
Download or read book Theoretical Foundations and Application of Photonic Crystals written by Alexander Vakhrushev and published by BoD – Books on Demand. This book was released on 2018-04-04 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is devoted to the description of research and design of photonic crystals. Topics included in the book cover a wide range of research in the field of theoretical analysis and experimental investigation: the electromagnetic field in the photonic crystal, propagation of waves in the gyrotropic magnetophotonic crystals, low one-photon absorption, ultratransparent photonic crystals, colloidal assembly, photonic crystal application for development of all-optical computational system, design strategies for PC devices, self-organization of liquid crystalline nanostructures, and optical diodes. This book will be useful for engineers, technologists, researchers, and postgraduate students interested in the research, design, fabrication processes, and applications of photonic crystals.
Download or read book Chemically Tunable Colloidal Photonic Crystals written by André C. Arsenault and published by . This book was released on 2007 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photonic crystals are a novel class of materials which experience a spatially periodic modulation in their refractive index. A periodicity at the length scale of the wavelength of photons can exert an exquisite control over the flow of light passing through these materials. In this thesis I explore colloidal photonic crystals fabricated through bottom-up self-assembly techniques, and probe how their properties can be tuned through chemical means.The next section of my thesis describes the synthesis and properties of porous and elastic photonic crystals. These materials can be compressed with small forces, generating concomitant changes in optical properties. This mechanical response was used to image microstructured stamps as well as human fingerprints. The porous framework of the material, on the other hand, was used to house luminescent nanoclusters. The interplay of photoluminescence and the modified photonic density of states due to the photonic crystal resulted in highly tunable light emission.The thesis follows with a section on "smart" planar defects within colloidal photonic crystals. The defects are synthesized by layer-by-layer electrostatic self-assembly, a method with incredible compositional diversity. Sensors could thus be created, responsive to organic vapors, light, temperature, redox agents, and biochemically relevant molecules such as DNA.The final section of my thesis explores the use of colloidal photonic crystal templates for confined self-assembly processes. I first looked at polyelectrolyte self-assembly in these confines, and found a dramatic influence on the deposition process. I then looked at block copolymer self-assembly in these spaces, and found that the proximity of interfaces in the structure could generate unprecedented nanostructures.The first section of my thesis deals with metallopolymer-based swellable photonic crystals. Exposure to stimuli such as solvents, vapors, and redox agents can affect the volume of the metallopolymer component and modulate reflected colors from the photonic crystal. In addition, the redox-activity of these materials has allowed their incorporation into electrochemical cells which could form the basis of next generation color displays.
Download or read book Photonic Crystals written by Kurt Busch and published by John Wiley & Sons. This book was released on 2006-05-12 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of the contributions in this topically edited book stems from the priority program SPP 1113 "Photonische Kristalle" run by the Deutsche Forschungsgemeinschaft (DFG), resulting in a survey of the current state of photonic crystal research in Germany. The first part of the book describes methods for the theoretical analysis of their optical properties as well as the results. The main part is dedicated to the fabrication, characterization and modeling of two- and three-dimensional photonic crystals, while the final section presents a wide spectrum of applications: gas sensors, micro-lasers, and photonic crystal fibers. Illustrated in full color, this book is not only of interest to advanced students and researchers in physics, electrical engineering, and material science, but also to company R&D departments involved in photonic crystal-related technological developments.
Download or read book Photonic Crystals written by Jean-Michel Lourtioz and published by Springer. This book was released on 2010-10-19 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the theoretical background required for modelling photonic crystals and their optical properties, while presenting the large variety of devices where photonic crystals have found application. As such, it aims at building bridges between optics, electromagnetism and solid state physics. This second edition includes the most recent developments of two-dimensional photonic crystal devices, as well as some of the last results reported on metamaterials.
Download or read book Colloidal Photonic Crystal Stationary Phases written by Ulrich Kamp and published by . This book was released on 2007 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chromatography, the separation of complex molecule mixtures, is a very powerful analytical technique. Since its invention a century ago it has been continuously adapted and developed. Particulate beds are at the verge of being exchanged for continuous monolithic beds, columns lengths are shrinking towards the centimeter range. Research is driven by a demand for ever more efficient chromatography and integrated separation and analysis systems on chips.In twenty years the concept of light localization in three-dimensional periodic structures has created the constantly expanding field of photonic crystals. A facile bottom-up approach to photonic structures is the self-assembly of monodisperse colloidal microspheres. Emerging applications are non-linear optical devices, structural colors, and refractive index change sensitive sensors. There exists a continuous search for additional and alternative uses to benefit and apply gained knowledge from the colloidal photonic crystal research.The ideal particulate chromatographic stationary phase and the colloidal crystal structure share a related and comparable building plan. It is an appealing concept to merge aspects of these two fields. A synthesis of stationary phase and optically responsive crystal could lead to an actively sensing chromatographic bed.Here we produce colloidal photonic crystal films, monoliths, columns and their inverse constructs. The structures are examined for their structural and optical properties, as well as their suitability for optically responsive separation phases. An image processing method measuring refractive indices and refractive index changes is developed, which is based on the optical response of colloidal photonic crystal films and capillaries. Capillary colloidal crystals are brought to an applicable stage and are integrated into a nanovolume liquid chromatography system as microbore capillary columns.
Download or read book Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography written by Ying-Chieh Chen and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Multibeam interference lithography is investigated as a manufacturing technique for three-dimensional photonic crystal templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical spectroscopy. Theoretical spectra are calculated and demonstrate close agreement with experimental values, indicating that this fabrication process achieves excellent optical quality. X-ray microscopy provides non-destructive inspection of the fabricated crystals at nano-scale resolution. A reconstructed crystal model is generated by computed tomography which allows for comparison to a predicted structure's geometry and optical spectra. Using the polymer crystal as a template, electrodeposition is performed to completely infiltrate the crystal with Cu2O. After polymer removal the inverted Cu2O crystal exhibits a high peak reflectance at the predicted wavelength, indicating the structure is an exact inverse of the template. A conformal growth algorithm is developed for the commonly used chemical vapor deposition infiltration technique to explain growth results and verified experimentally with atomic layer deposition of oxide materials. Finally, a customized chemically amplified positive photoresist system and its processing steps are developed as a route to zero-shrinkage template material for high fidelity patterning of the designed interference patterns.
Download or read book Theoretical Foundations and Application of Photonic Crystals written by Alexander Vakhrushev and published by . This book was released on 2018 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is devoted to the description of research and design of photonic crystals. Topics included in the book cover a wide range of research in the field of theoretical analysis and experimental investigation: the electromagnetic field in the photonic crystal, propagation of waves in the gyrotropic magnetophotonic crystals, low one-photon absorption, ultratransparent photonic crystals, colloidal assembly, photonic crystal application for development of all-optical computational system, design strategies for PC devices, self-organization of liquid crystalline nanostructures, and optical diodes. This book will be useful for engineers, technologists, researchers, and postgraduate students interested in the research, design, fabrication processes, and applications of photonic crystals.
Download or read book Physics and Engineering of New Materials written by Do Tran Cat and published by Springer Science & Business Media. This book was released on 2009-01-01 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the majority of the contributions to the Tenth German-Vietnamese Seminar on Physics and Engineering (GVS10) that took place in the Gustav- Stresemann-Institut (GSI) in Bonn from June 6 to June 9, 2007. In the focus of these studies are the preparation and basic properties of new material systems, related investigation methods, and practical applications. Accordingly the sections in this book are entitled electrons: transport and confinement, low-dimensional systems, magnetism, oxidic materials, organic films, new materials, and methods. The series of German-Vietnamese seminars was initiated and sponsored by the Gottlieb Daimler- and Karl Benz -Foundation since 1998 and took place alt- nately in both countries. These bilateral meetings brought together top-notch senior and junior Vietnamese scientists with German Scientists and stimulated many contacts and co-operations. Under the general title “Physics and Engine- ing” the programs covered, in the form of keynote-lectures, oral presentations and posters, experimental and theoretical cutting-edge material-physics oriented topics. The majority of the contributions was dealing with modern topics of material science, particularly nanoscience, which is a research field of high importance also in Vietnam. Modern material science allows a quick transfer of research results to technical applications, which is very useful for fast developing countries like Vietnam. On the other hand, the seminars took profit from the strong cro- fertilization of the different disciplines of physics. This book is dedicated to the tenth anniversary of the seminars and nicely shows the scientific progress in Vietnam and the competitive level reached.
Download or read book New Trends in Lyotropic Liquid Crystals written by Ingo Dierking and published by MDPI. This book was released on 2020-11-02 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystals (LCs) were discovered more than a century ago, and were, for a long time, treated as a physical curiosity, until the development of flat panel screens and display devices caused a revolution in the information display industry, and in fact in society. There would be no mobile phones without liquid crystals, no flat screen TVs or computer monitors, no virtual reality, just to name a few of the applications that have changed our whole world of vision and perception. All of these inventions are based on liquid crystals that are formed through a change in temperature, thermotropic LCs. However, there is another form of liquid crystals, described even earlier, yet much less talked about; the lyotropic liquid crystals that occur through the change of concentration of some molecules in a solvent. These are found in abundance in nature, making up the cell membranes, and are used extensively in the food, detergents and cosmetics industries. In this collection of articles by experts in their respective research areas, we bring together some of the most recent and innovative aspects of lyotropic liquid crystals, which we believe will drive future research and set novel trends in this field.
Download or read book Laser Precision Microfabrication written by Koji Sugioka and published by Springer. This book was released on 2010-08-13 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.
Download or read book Electrochemistry of Metal Chalcogenides written by Mirtat Bouroushian and published by Springer Science & Business Media. This book was released on 2010-04-23 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author provides a unified account of the electrochemical material science of metal chalcogenide (MCh) compounds and alloys with regard to their synthesis, processing and applications. Starting with the chemical fundamentals of the chalcogens and their major compounds, the initial part of the book includes a systematic description of the MCh solids on the basis of the Periodic Table in terms of their structures and key properties. This is followed by a general discussion on the electrochemistry of chalcogen species, and the principles underlying the electrochemical formation of inorganic compounds/alloys. The core of the book offers an insight into available experimental results and inferences regarding the electrochemical preparation and microstructural control of conventional and novel MCh structures. It also aims to survey their photoelectrochemistry, both from a material-oriented point of view and as connected to specific processes such as photocatalysis and solar energy conversion. Finally, the book illustrates the relevance of MCh materials to various applications of electrochemical interest such as (electro)catalysis in fuel cells, energy storage with intercalation electrodes, and ion sensing.
Download or read book Next Generation of Photovoltaics written by Ana Cristobal and published by Springer Science & Business Media. This book was released on 2012-02-16 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents new concepts for a next generation of PV. Among these concepts are: Multijunction solar cells, multiple excitation solar cells (or how to take benefit of high energy photons for the creation of more than one electron hole-pair), intermediate band solar cells (or how to take advantage of below band-gap energy photons) and related technologies (for quantum dots, nitrides, thin films), advanced light management approaches (plasmonics). Written by world-class experts in next generation photovoltaics this book is an essential reference guide accessible to both beginners and experts working with solar cell technology. The book deeply analyzes the current state-of-the-art of the new photovoltaic approaches and outlines the implementation paths of these advanced devices. Topics addressed range from the fundamentals to the description of state-of-the-art of the new types of solar cells.
Download or read book Raman and SERS Investigations of Pharmaceuticals written by Monica Baia and published by Springer Science & Business Media. This book was released on 2008-06-11 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last several years it has become apparent to most researchers that interdisciplinary research is the key to success in the sciences’ future. The present book exemplifies such interdisciplinary work. Thus, some new derivatives have been prepared by chemists and consecutively analyzed by physicists in order to better understand their physical-chemical properties for future tests to be performed by pharmacists. The book consists of an introductory section and other eight chapters. First, the fundamentals of infrared, Raman and surface-enhanced Raman spectroscopy and those of the theoretical methods employed for the vibrational prediction modes are highlighted. The SERS investigations illustrated in the following chapters are focused on different kinds of drugs: tranquilizers and sedatives, anti-inflammatory drugs, vitamins, drugs with anti-bacterial properties, etc. Since there is an increased interest in designing highly effective and controllable SERS-active substrates, a few newly developed substrates that could contribute to a deeper understanding and knowledge of the adsorption behavior of various types of molecules of pharmaceutical and medical interest are also presented.
Download or read book Cellulose Nanocrystals written by Wadood Y. Hamad and published by John Wiley & Sons. This book was released on 2017-04-17 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research into cellulose nanocrystals is currently in an exponential growth phase, with research into potential applications now strengthened by recent advances in nanomanufacturing. The possibility of routine commercial production of these advanced materials is now becoming a reality. Cellulose Nanocrystals: Properties, Production and Applications provides an in-depth overview of the materials science, chemistry and physics of cellulose nanocrystals, and the technical development of advanced materials based on cellulose nanocrystals for industrial and medical applications. Topics covered include: • A comprehensive treatment of the structure, morphology and synthesis of cellulose nanocrystals. • The science and engineering of producing cellulose nanocrystals and the challenges involved in nanomanufacturing on a large industrial scale. • Surface/interface modifications of cellulose nanocrystals for the development of novel biomaterials with attractive structural and functional properties. • The scientific bases for developing cellulose-based nanomaterials with advanced functionalities for industrial/medical applications and consumer products. • Discussions on the (i) reinforcing potential of cellulose nanocrystals in polymer nanocomposites, (ii) utilization of these nanocrystals as efficient templates for developing tunable photonic materials, as well as (iii) applications in sustainable electronics and biomedicine. Cellulose Nanocrystals: Properties, Production and Applications will appeal to audiences in the physical, chemical and biological sciences as well as engineering disciplines. It will be of critical interest to industrialists seeking to develop sustainable new materials for the advanced industrial economies of the 21st century, ranging from adaptive “smart” packaging materials, to new chiral, mesoporous materials for optoelectronics and photonics , to high-performance nanocomposites for structural applications.
