Download or read book Nonlinear materials for optical power limiting written by Hampus Lundén and published by Linköping University Electronic Press. This book was released on 2019-05-13 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: High power laser pulses can be a threat to optical sensors, including the human eye. Traditionally this threat has been alleviated by colour filters that block radiation in chosen wavelength ranges. Colour filters’ main drawback is that they block radiation regardless of it being useful or damaging, information is lost for wavelengths at which the filter is active. Protecting the entire wavelength range of a sensor would block or strongly attenuate the radiation needed for the operation of the sensor. Sol-gel glasses highly doped with optically non-linear chromophores have previously shown high optical quality in combination with efficient optical power limiting (OPL) through reverse saturable absorption (RSA). These filters transmit visible light unless the light fluence is above a certain threshold. A key design consideration of laser protection filters is linear absorption in relation to the threshold level. A high linear absorption means that the user’s view is degraded by the filter. To model the photokinetics of RSA chromophores, the five-level population model is widely used. It consists of three singlet and two triplet levels. Model parameters relevant for OPL performance include linear absorption cross-sections, two-photon absorption (2PA) cross-sections, lifetimes, quantum yields and inter-system-crossing (ISC) times. The dominant design paradigm is to have a highly absorbing and long-lived triplet state that is quickly populated by ISC during the beginning of a laser pulse. To simultaneously achieve a lower threshold and linear absorption a vast number of materials for self-activated filters were evaluated, either as bulk glasses or solutions. An f/5 setup was used to evaluate their OPL performance while several photophysical measurements were performed to gain an understanding of system behaviour. The first three series of methyltriethoxysilane (MTEOS) Sol-Gel glasses were doped with gold nanoparticles either solely, or with one of two Pt-acetylide chromophores. One with shorter conjugated ligands, the second with similar but longer conjugated ligands. Finally, a series of multi-branched fluorene chromophores were evaluated in solution. Their central moiety was either an organic benzene unit or an ISC promoter in the form of para-dibromobenzene or a platinum(II)-alkynyl unit. For the gold nanoparticle doped glasses, the lower performance Pt-acetylide with short ligands had its OPL threshold lowered at 600nm while the glasses doped with only gold nanoparticles showed no OPL at all. Secondly, the enhancement was most pronounced for very low gold nanoparticle concentrations. While gold nanoparticles alone showed good OPL performance at 532 nm, at this wavelength neither Pt-acetylide showed an obvious OPL enhancement beyond linear absorption losses from codoping with gold nanoparticles. The improved OPL performance at 600 nm was attributed to stronger 2PA, by electric field enhancement from the gold nanoparticles. The lack of detectable OPL improvement for 532 nm and for the higher performance Pt-Acetylide chromophore with long ligands were qualitatively explained by a lower sensitivity to 2PA on system performance. A degraded performance from linear absorption by excess nanoparticles in front of the focus explained the weakening of the enhancement at higher gold nanoparticle concentrations. All three fluorene chromophores, including the chromophore without a central ISC promoter, showed broadband OPL through the visible spectrum. The OPL performance of the two chromophores with ISC promoters was expected considering their transient absorption at microsecond time-scales. For the fluorene chromophore without an ISC-promoter, ultra-fast transient absorption was used to identify singlet excited state absorption as the source of the OPL performance. Both of these series of experiments demonstrate how a simplistic view of simply increasing desired photophysical parameters, e.g. effective 2PA cross-section or ISC quantum yield, do not always result in a noticeable increase in system performance. By employing numerical population models it was possible to identify which parameters had the highest impact on OPL performance. Laserpulser med hög effekt kan vara ett hot mot optiska sensorer, inklusive det oskyddade ögat. Traditionellt har detta hot hanterats med färgfilter som stoppar strålning inom valda våglängdsband. Färgfilters huvudsakliga begränsning ligger i att de tar bort strålning oberoende av om den är användbar eller skadlig, att information försvinner för de våglängder filtret skyddar för. Skydd över hela det våglängdsband en sensor verkar i skulle stoppa eller kraftigt försvaga strålningen som sensorn behöver för att fungera. Sol-gel glas högdopade med optiskt icke-linjära molekyler har tidigare visat hög optisk kvalité i kombination med en effektiv optisk effektbegränsning (OPL) via omvänd blekning (RSA). Dessa filter transmitterar synligt ljus så länge ljusets fluens (pulsenergi per area [J cm-2]) inte ligger över en viss begränsningsnivå. En nyckelfaktor i designen av laserskyddsfilter är linjärabsorption kontra begränsningsnivå. Genom att öka kromoforkoncentrationen så kan begränsningsnivån sänkas till kostnad av ökad linjärabsorption. Detta betyder dock att användarens omvärldsuppfattning genom filtret riskerar att minska. För att modellera fotokinetiken av RSA-molekyler har femnivåpopulationsmodellen varit vida använd. Den består av tre singlet-nivåer och två tripletnivåer. Modellparametrar relevanta för OPL-prestanda innefattar kvantverkningsgrader, olika övergångars linjärabsorptionstvärsnitt, tvåfotonsabsorptionstvärsnitt och livstider samt halveringstider för överföring mellan singlet och triplettillstånd. Den dominanta designparadigmen är att ha ett hög- absorberande och långlivat tripletläge som snabbt populeras i början av en laserpuls. För att samtidigt uppnå en lägre begränsningsnivå och lägre linjärabsorption utvärderades ett flertal självaktiverade filter, antingen i form av glas eller i vätskelösning. En f/5-uppställning användes för att utvärdera deras OPLprestanda medan en mängd fotofysiska mätningar utfördes för att få en förståelse för deras systembeteende. De tre första serierna av MTEOS Sol-Gel glas var dopade med guldnanopartiklar antingen enbart, eller med en av två Pt(II)-acetylidmolekyler. Den första hade kortare konjugerade ligandarmar, den andra var liknande men hade längre ligandarmar. Slutligen utvärderades en serie av flerarmade flourenmolekyler i vätskelösning. Deras centrala enhet bestod antingen av en organisk bensenring eller en ISC-gynnare i form av para-dibromobensen eller en Pt(II)-acetylidenhet. Guldnanopartiklarna kunde förstärka OPL-prestandan för enbart den mindre effektiva korta Pt(II)-acetylidmolekylen på 600nm men ej 532nm. Filtren dopade med enbart guldnanopartiklar visade god prestanda på 532nm men ingen på 600nm. Alla tre fluorenmolekyler visade OPL genom det synliga spektrat, även den molekylen utan ISC-gynnare. Både dessa serier experiment demonstrerar hur ett förenklat angreppsätt med att enbart öka eftertraktade fotofysiska parametrar, t.ex. effektivt 2PA-tvärsnitt eller ISC-kvantverkningsgrad, inte alltid resulterar i märkbart ökad systemprestanda. Genom att använda numeriska populationsmodeller visas hur det är möjligt att identifiera vilka parametrar som har den största inverkan på OPL-prestanda.

Download or read book Nonlinear Optical Materials for Switching and Limiting written by M. J. Soileau and published by . This book was released on 1994 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the First International Workshop on Optical Power Limiting written by Francois Kajzar and published by CRC Press. This book was released on 1999 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contemporary Nonlinear Optics written by Robert Boyd and published by Academic Press. This book was released on 2012-12-02 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contemporary Nonlinear Optics discusses the different activities in the field of nonlinear optics. The book is comprised of 10 chapters. Chapter 1 presents a description of the field of nonlinear guided-wave optics. Chapter 2 surveys a new branch of nonlinear optics under the heading optical solitons. Chapter 3 reviews recent progress in the field of optical phase conjugation. Chapter 4 discusses ultrafast nonlinear optics, a field that is growing rapidly with the ability of generating and controlling femtosecond optical pulses. Chapter 5 examines a branch of nonlinear optics that may be termed nonlinear quantum optics. Chapter 6 reviews the new field of photorefractive adaptive neural networks. Chapter 7 presents a discussion of recent successes in the development of nonlinear optical media based on organic materials. Chapter 8 reviews the field of nonlinear optics in quantum confined structures. Chapter 9 reviews the field of nonlinear laser spectroscopy, with emphasis on advances made during the 1980s. Finally, Chapter 10 reviews the field of nonlinear optical dynamics by considering nonlinear optical systems that exhibit temporal, spatial, or spatio-temporal instabilities. This book is a valuable source for physicists and other scientists interested in optical systems and neural networks.

Download or read book Nonlinear Optical Spectroscopy of Inorganic Materials Nanoparticles written by Devbrat Pundhir and published by LAP Lambert Academic Publishing. This book was released on 2014-02 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the scenario, nonlinear optics is very important due the large number of applications such as optical limiting, image processing and nonlinear devices etc. There are considerable research efforts to study the mechanisms of optical power limiting, synthesize new materials and develop devices with advanced properties. An optical limiter is a device that strongly attenuates optical beam to a threshold level at high intensity while exhibits linear transmittance at low intensity. Such devices are used for protecting human eyes and optical sensors from damage due to exposure to intense radiation. The search for efficient optical limiters has lead to the study of various materials. This book is dealing with the problem of new materials and characterize them using Z-scan technique, it will be very helpful for the researchers and students who are working in the area of Nonlinear Optics.

Download or read book Nonlinear Optical Properties of Materials written by Rashid A. Ganeev and published by Springer. This book was released on 2013-01-09 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is mostly concerned on the experimental research of the nonlinear optical characteristics of various media, low- and high-order harmonic generation in different materials, and formation, and nonlinear optical characterization of clusters. We also demonstrate the inter-connection between these areas of nonlinear optics. Nonlinear optical properties of media such as optical limiting can be applied in various areas of science and technology. To define suitable materials for these applications, one has to carefully analyse the nonlinear optical characteristics of various media, such as the nonlinear refractive indices, coefficients of nonlinear absorption, saturation absorption intensities, etc. Knowing the nonlinear optical parameters of materials is also important for describing the propagation effects, self-interaction of intense laser pulses, and optimisation of various nonlinear optical processes. Among those processes one can admit the importance of the studies of the frequency conversion of coherent laser sources. The area of interest for nonlinear optical characterization of materials is also closely related with new field of nanostructures formation and application during laser-matter interaction. We show how the nonlinear optical analysis of materials leads to improvement of their high-order nonlinear optical response during the interaction with strong laser fields. Ablation-induced nanoparticles formation is correlated with their applications as efficient sources of coherent short-wavelength photons. From other side, recent achievements of harmonic generation in plasmas are closely related with the knowledge of the properties of materials in the laser plumes. All of these studies are concerned with the low-order nonlinear optical features of various materials. The novelty of the approach developed in present book is related with inter-connection of those studies with each other.

Download or read book Basic Studies of Nonlinear Optical Materials for Eye and Sensor Protection written by and published by . This book was released on 2000 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the basic spectroscopy, kinetics and nonlinear optical properties of a set of power limiting materials, which include six metallobenzoporphyrins and ten donor-acceptor azulenic molecules. These compounds are known to have highly polarizable it-electrons, and therefore are expected to have nonlinear coefficients suitable for utilization in optical limiting devices. In order to diagnose the optical limiting properties of the materials, we developed new two-dimensional Z-scan technique. This technique allows us to measure separately real and imaginary parts of the third order nonlinear susceptibility X(3) of the materials, using arbitrarily beam shaped laser pulse and arbitrary sample thickness. In addition, the beam profile evolution anywhere inside the optical limiting material can be extracted accurately using 2D Z-scan technique. We have tested this technique using Gaussian and non-Gaussian special beam distributions, thin and thick samples, and applied it to the molecules studied. Some of the molecules showed high nonlinear absorption and nonlinear refraction at the wavelength of the experiment 527 nm.

Download or read book Nonlinear Optical Liquids for Power Limiting and Imaging written by Christopher M. Lawson and published by . This book was released on 1998 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Optical Effects an Optical Power Limiter written by Stanford University. Stanford Electronics Laboratories and published by . This book was released on 1962 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Optical Effects and Materials written by Peter Günter and published by Springer. This book was released on 2012-12-06 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describing progress achieved in the field of nonlinear optics and nonlinear optical materials, the Handbook treats selected topics such as photorefractive materials, third-order nonlinear optical materials and organic nonlinear optical crystals, as well as electro-optic polymers. Applications of photorefractive materials in optical memories, optical processing, and guided-wave nonlinear optics in hotorefractive waveguides are described. As light will play a more and more dominant role as an information carrier, the review of existing and new materials given here makes this a keystone book in the field.

Download or read book Hybrid Nonlinear Optical Materials for Applications in Power Limiting and Photorefractive Devices written by and published by . This book was released on 2010 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the period covered by this project, our research efforts have been focused on the following subjects: (1) designing and synthesizing highly multi-photon active organic chromophores, (2) exploring novel organic/inorganic composite materials and enhanced mechanisms for optical limiting applications, and (3) utilizing nano-technology to improve the performance of organic photorefractive materials working in IR wavelength range. Since 2008, we have successfully synthesized two groups of chromophores that exhibit high two-photon absorbability: one is a group of laddertype oligo-p-phenylene cored chromophores useful for optical limiting; the other is a nitrosyl complex for light activated therapy through nitric oxide release. From the view-point of optical limiting applications, a solid two-photon absorbing material is much better than a solution or liquid medium, therefore we have developed a novel chromophore (AF289) doped polystyrene rod system, which manifests an excellent chemical/physical stability and provides a superior optical limiting and stabilization capability working with tilde 800-nm and tilde 160-fs laser pulses. In respect to photorefractive study, our other recent achievement is the optimization of photosensitivity in hybrid nano-composites containing lead sulfide (PbS) nanoparticles (NPs) with optical activity in near-infrared (NIR) spectral range. To improve the optoelectronic properties, we have applied a ligand de-protection strategy to demonstrate a relative improvement in the efficiency of a charge generation of hybrid PR composites for PR applications. The resulting shortened ligands on NCs lead to enhancement of both photocurrent and diffraction efficiency in corresponding film devices. As a result, the photon generation quantum efficiency in photoconductivity study was improved to be over 20%, and the two-beam coupling (TBC) gain coefficient was pronounced as 173 cm( -1).

Download or read book Nonlinear Optical Liquids and Power Limiters written by Christopher M. Lawson and published by SPIE-International Society for Optical Engineering. This book was released on 1997 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book External Nonlinear Focusing and Its Application to Ultrafast Optical Power Limiting written by J. A. Hermann and published by . This book was released on 1986 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple model for external self-focusing or defocusing of a laser beam by a thin nonlinear phase corrector has been explored by numerical computation and by mathematical analysis. Utilising the mechanisms of nonlinear absorption and refraction, it is shown how passive and ultrafast power- or energy-limiting device can be constructed, with the ultimate aim of protecting optical or infrared equipment from excessive laser powers. (Australia).

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.

Download or read book Nonlinear Optical Materials Principles and Applications written by Società italiana di fisica and published by IOS Press. This book was released on 1995 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear optical materials play a pivotal role in the future evolution of nonlinear optics in general and its impact in technology and industrial applications in particular. The progress in nonlinear optics has been tremendous since the first demonstration of an all-optical nonlinear effect in the early sixties, but until recently the main visible emphasis was on the physical aspects of the nonlinear radiation matter interaction. In the last decade, however, this effort has also brought its fruits in applied aspects of nonlinear optics. This can be essentially traced to the improvement of the performances of the nonlinear optical materials. Our understanding of the nonlinear polarization mechanisms and their relation to the structural characteristics of the materials has been considerably improved. In addition, the new development of techniques for the fabrication and growth of artificial materials has dramatically contributed to this evolution. The goal is to find and develop materials presenting large nonlinearities and satisfying at the same time all the technological requirements for applications such as wide transparency range, fast response, high damage threshold but also processability, adaptability and interfacing with other materials. Improvements, besides rendering possible the implementation of nonlinear effects in devices, open the way to the study of new nonlinear optical effects and the introduction of new concepts. This book describes new concepts which are emerging in the field of nonlinear optical materials, concentrating the attention on materials which seem more promising for applications in the technology of information transmission and processing.

Download or read book Principles and Applications of Nonlinear Optical Materials written by R.W. Munn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear optics is a topic of much current interest that exhibits a great diversity. Some publications on the subject are clearly physics, while others reveal an engineering bias; some appear to be accessible to the chemist, while others may appeal to biological understanding. Yet all purport to be non linear optics so where is the underlying unity? The answer is that the unity lies in the phenomena and the devices that exploit them, while the diversity lies in the materials used to express the phenomena. This book is an attempt to show this unity in diversity by bringing together contributions covering an unusually wide range of materials, preceded by accounts of the main phenomena and important devices. Because ofthe diversity, individual materials are treated in separate chapters by different expert authors, while as editors we have shouldered the task of providing the unifying initial chapters. Most main classes of nonlinear optical solids are treated: semiconductors, glasses, ferroelectrics, molecular crystals, polymers, and Langmuir-Blodgett films. (However, liquid crystals are not covered. ) Each class of material is enough for a monograph in itself, and this book is designed to be an introduction suitable for graduate students and those in industry entering the area of nonlinear optics. It is also suitable in parts for final-year undergraduates on project work. It aims to provide a bridge between traditional fields of expertise and the broader field of nonlinear optics.

Download or read book Nonlinear Optics written by Robert W. Boyd and published by Elsevier. This book was released on 2003-01-07 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Optical Society of America (OSA) and SPIE – The International Society for Optical Engineering have awarded Robert Boyd with an honorable mention for the Joseph W. Goodman Book Writing Award for his work on Nonlinear Optics, 2nd edition.Nonlinear optics is essentially the study of the interaction of strong laser light with matter. It lies at the basis of the field of photonics, the use of light fields to control other light fields and to perform logical operations. Some of the topics of this book include the fundamentals and applications of optical systems based on the nonlinear interaction of light with matter. Topics to be treated include: mechanisms of optical nonlinearity, second-harmonic and sum- and difference-frequency generation, photonics and optical logic, optical self-action effects including self-focusing and optical soliton formation, optical phase conjugation, stimulated Brillouin and stimulated Raman scattering, and selection criteria of nonlinear optical materials. · Covers all the latest topics and technology in this ever-evolving area of study that forms the backbone of the major applications of optical technology· Offers first-rate instructive style making it ideal for self-study· Emphasizes the fundamentals of non-linear optics rather than focus on particular applications that are constantly changing