Laser Technology

This book highlights the photogalvanic effects at low dimensions, surfaces, and interfaces, more specifically 2D materials, such as graphene and monolayer transition metal dichalcogenides. Although the phenomenology of the photogalvanic effects, which can be simply seen as photoresponse nonlinear-in-electric field, have been well-established, the microscopic understanding in each material system may vary. This book is a quick reference and a detailed roadmap starting from phenomenology and continuing with the ultimate low dimensional materials, in which the photogalvanic effects can offer a rich platform at the second-order response to an electric field. A general phenomenology of photogalvanic effect is provided in the first chapter, together with the photon drag effect which also generates a photocurrent like the photogalvanic effect, but with some distinct features, as well as somewhat puzzling similarities. Next two chapters explain these effects in graphene, starting with a necessary related background on graphene, then a particular focus on its specific phenomenology, microscopic theory, and experimental results. In a similar fashion, in chapters four and five, a necessary background for the photogalvanic effects in monolayer transition metal dichalcogenides, with symmetry analysis, microscopic theory, and experimental results is presented, along with the Berry curvature dependent photocurrent, which can also play an important role in 2D semiconductors. The second-order photogalvanic effects that have been covered so far in graphene and monolayer transition metal chalcogenides have already excited the 2D semiconductor optoelectronic research community by several means. It seems that the interests on the photogalvanic effects will continue to escalate in near future.

This book, now in its fourth edition, is a well-known classic on the ultrafast nonlinear and linear processes responsible for supercontinuum generation. The book begins with chapters reviewing the experimental and theoretical understanding of the field along with key applications developed since the discovery of the supercontinuum effect. The chapters that follow cover recent research activity on supercontinuum phenomena, novel applications, and advances achieved since the publication of the previous edition. The new chapters focus on: filamentation in gases, air, and condensed media; conical emission by four-wave mixing and X-waves; electronic self-phase mechanism; higher harmonics generation; attosecond laser pulses; complex vector beam supercontinuum; higher order self-phase modulation and cross-phase modulation; nonlinear supercontinuum interference in uniaxial crystals; new nonlinear microscopes involving supercontinuum and ultrafast lasers with biomedical applications; and other current supercontinuum applications in communications.The Supercontinuum Laser Source is a definitive work by one of the discoverers of the white light effect. It is indispensable reading for any researcher or student working in the field of ultrafast laser physics.Chapter 6 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

Paperback

Book

Optik,Laser, Wellenleiter stellt eine Einführung in die angewandte Optik dar. Dabei werden nicht nur Strahlenoptik mit optischen Instrumenten, Lichtquellen und Detektoren einerseits sowie Wellenoptik mit Interferometrie andererseits behandelt; es wird auch ausführlich auf Holographie, Laser, Kohärenz, Faseroptik, Wellenleiter und integrierte Optik eingegangen. Die physikalischen Grundlagen, Anwendungen und die Instrumentierung stehen dabei stets im Vordergrund. Mehr als 100 Übungen dienen der Vertiefung des Stoffes. Das Buch ist sowohl als vorlesungsbegleitende Lektüre für Studenten als auch als Nachschlagewerk für Diplomanden, Wissenschaftler und Praktiker geeignet.

Bringing together contributions from leading experts in the field, this book reviews laser processing concepts that allow the structuring of material beyond optical limits, and methods that facilitate direct observation of the underlying mechanisms by exploring direct structuring and self-organization phenomena. The capacity to nanostructure material using ultrafast lasers lays the groundwork for the next generation of flexible and precise material processing tools. Rapid access to scales of 100 nm and below in two and three dimensions becomes a factor of paramount importance to engineer materials and to design innovative functions. To reflect the dynamic nature of the field at all levels from basic science to applications, the book is divided into three parts, Fundamental Processes, Concepts of Extreme Nanostructuring, and Applications, each of which is comprehensively covered. This book will be a useful resource for graduate students and researchers in laser processing, materials engineering, and nanoscience.

Dieses Buch gibt darüber Aufschluss, wie die Prozessstabilität als Maß für die Qualitätssicherung mit der Spritzerintensität korreliert und welche Einflussgrößen diese beeinflussen. Innerhalb der durchgeführten Arbeiten wurde zunächst ein methodisches Vorgehen zur Quantifizierung der Prozessinstabilitäten auf Basis der resultierenden Anzahl an Prozessspritzern entwickelt, wobei diese Methodik in mehreren darauffolgenden Schritten dazu verwendet wurde, um gezielt die Auswirkungen einiger ausgewählter Einfluss- und Stellgrößen im Kontext der PBF-LB/M-Prozessstabilität zu untersuchen und innerhalb einer Potenzialanalyse zur spritzerreduzierten Prozessführung zu bewerten. Dabei wurden neben den grundlegenden Prozessparametern (Schichtstärke, Fokusdurchmesser, Laserleistung, Scangeschwindigkeit, Hatch-Abstand und der Gasstromwinkel) auch der vorherrschende Umgebungsdruck in der Prozesskammer, das verwendete Inertgas, einige Eigenschaften des Pulvermaterials sowie die Auswirkungen unterschiedlicher Laserstrahlformen hinsichtlich der resultierenden Anzahl an Prozessspritzern untersucht. Weiterführend wurde eine Wirtschaftlichkeitsanalyse durchgeführt, die sich sowohl mit Potenzialen zur Steigerung der Produktivität der einzelnen Stellgrößen als auch mit einer Kostenbetrachtung anhand eines Fallbeispiels in unterschiedlichen Szenarien beschäftigt.

HC runder Rücken kaschiert

This open access book is devoted to the theoretical and experimental studies of a novel accelerator light source mechanism called steady-state microbunching (SSMB) which promises high-power, high-repetition rate, narrow-band coherent radiation in an electron storage ring. The contribution of this dissertation consists of three parts: first, answers the question of how to realize SSMB from a beam dynamics perspective; second, reveals what radiation characteristics can we obtain from the formed SSMB; and third, experimentally demonstrates the working mechanism of SSMB in a real machine for the first time. The highlights of this book can be summarized as: Presents the first proof-of-principle experiment of a promising accelerator light source mechanism; Covers precision longitudinal and transverse-longitudinal coupling dynamics in a storage ring; Provides useful formulas and example parameters for high-power infrared, EUVand soft X-ray light source design.

This book discusses light, its properties as an electromagnetic wave, interaction with matter, and laser as an optical device. The first part discussions include qualitative arguments such as pictorial representations of the wave dynamics and analogy to other oscillatory systems to facilitate an intuitive understanding of the topics. The second part reviews light-matter interaction. It introduces the light-matter interaction while introducing the particular behavior of light, known as the photon, reviewing various properties of light waves resulting from the interaction with matters including the propagation of light in media. The last two sections focus on the fundamentals of lasers and the practical uses of lasers, including several techniques to control the spatial and temporal characteristics of laser beams. This book discusses acoustic waves' characteristics so that we can deepen our understanding of acoustic waves.

This book highlights the rapidly emerging field of solution-processed halide perovskite lasers. These amazing materials not only possess exceptional photovoltaic properties, but are also outstanding optical gain media. Halide perovskites are the latest member of solution-processed optical gain media, joining organics and traditional semiconductor colloidal quantum dots. Amplified spontaneous emission and lasing have been demonstrated in various halide perovskite configurations and nanostructures with wavelengths tunable over the visible and infrared wavelengths (400-1000 nm).This book provides comprehensive information on perovskite lasing, starting with some fundamentals of lasers and their basic operating principles. Unambiguous methods for identifying lasing light emission are presented, while the basic optoelectronic properties of perovskite materials are also discussed, with an emphasis on their photophysics, using ultrafast optical spectroscopy techniques. The viabilityof perovskites as a gain media within a suitable resonator, as well as the characterization methods for optical gain, are highlighted. The book closes with a discussion on the remaining challenges (such as electrical driven lasing and material stabilities) that need to be tackled, and the future of this new family of lasers.

In der vorliegenden Arbeit wird ein für das Selektive Lasersintern (SLS) geeigneter Polylactid-basierter Kompositwerkstoff sowie eine an diesen Werkstoff angepasste SLS-Prozessführung entwickelt. Als Füllstoffe werden ß-Tricalciumphosphat (ß-TCP) und Calciumcarbonat (CC) mit einem Gewichtsanteil von ca. 20-50¿% untersucht. Das Ziel ist die Entwicklung eines synthetischen Knochenersatzmaterials für die Additive Fertigung von patientenspezifischen bioresorbierbaren Implantaten.

This open access book describes the theory of transformation thermotics and its extended theories for the active control of macroscopic thermal phenomena of artificial systems, which is in sharp contrast to classical thermodynamics comprising the four thermodynamic laws for the passive description of macroscopic thermal phenomena of natural systems. This monograph consists of two parts, i.e., inside and outside metamaterials, and covers the basic concepts and mathematical methods, which are necessary to understand the thermal problems extensively investigated in physics, but also in other disciplines of engineering and materials. The analyses rely on models solved by analytical techniques accompanied by computer simulations and laboratory experiments. This monograph can not only be a bridge linking three first-class disciplines, i.e., physics, thermophysics, and materials science, but also contribute to interdisciplinary development.

This thesis investigates passively mode-locked semiconductor lasers by numerical methods. The understanding and optimization of such devices is crucial to the advancement of technologies such as optical data communication and dual comb spectroscopy. The focus of the thesis is therefore on the development of efficient numerical models, which are able both to perform larger parameter studies and to provide quantitative predictions. Along with that, visualization and evaluation techniques for the rich spatio-temporal laser dynamics are developed; these facilitate the physical interpretation of the observed features.The investigations in this thesis revolve around two specific semiconductor devices, namely a monolithically integrated three-section tapered quantum-dot laser and a V-shaped external cavity laser. In both cases, the simulations closely tie in with experimental results, which have been obtained in collaboration with the TU Darmstadt and the ETH Zurich. Based on the successful numerical reproduction of the experimental findings, the emission dynamics of both lasers can be understood in terms of the cavity geometry and the active medium dynamics. The latter, in particular, highlights the value of the developed simulation tools, since the fast charge-carrier dynamics are generally not experimentally accessible during mode-locking operation. Lastly, the numerical models are used to perform laser design explorations and thus to derive recommendations for further optimizations.

This book systematically describes the weld pool behavior in laser welding and its influencing factors from the perspectives of testing technology, theoretical calculation and process simulation technology, physical state transformation behavior of weld pools, and the impact of technical conditions on the weld pool behavior. The book covers extensive research achievements made in China in this field, some of which represent the latest cutting-edging researches conducted by the authors' research team. These latest research efforts mainly relate to the weld pool behavior of dual-beam laser welding, laser welding with filler wires, full-penetration laser welding of very-thick parts, and laser welding in vacuum and low vacuum conditions. The book is intended for undergraduate, graduate students and researchers who are interested in laser welding.

This open access book describes the theory of transformation thermotics and its extended theories for the active control of macroscopic thermal phenomena of artificial systems, which is in sharp contrast to classical thermodynamics comprising the four thermodynamic laws for the passive description of macroscopic thermal phenomena of natural systems. This monograph consists of two parts, i.e., inside and outside metamaterials, and covers the basic concepts and mathematical methods, which are necessary to understand the thermal problems extensively investigated in physics, but also in other disciplines of engineering and materials. The analyses rely on models solved by analytical techniques accompanied by computer simulations and laboratory experiments. This monograph can not only be a bridge linking three first-class disciplines, i.e., physics, thermophysics, and materials science, but also contribute to interdisciplinary development.

This thesis investigates the detection efficiency of field-resolved measurements of ultrashort mid-infrared waves via electro-optic sampling for the first time. Employing high-power gate pulses and phase-matched upconversion in thick nonlinear crystals, unprecedented efficiencies are achieved for octave-spanning fields in this wavelength range. In combination with state-of-the art, high-power, ultrashort mid-infrared sources, this allows to demonstrate a new regime of linear detection dynamic range for field strengths from mV/cm to MV/cm-levels. These results crucially contribute to the development of field-resolved spectrometers for early disease detection, as fundamental vibrational modes of (bio-)molecules lie in the investigated spectral range.The results are discussed and compared with previous sensitivity records for electric-field measurements and reference is made to related implementations of the described characterization technique. Including a detailed theoreticaldescription and simulation results, the work elucidates crucial scaling laws, characteristics and limitations. The thesis will thus serve as an educational introduction to the topic of field-resolved measurements using electro-optic sampling, giving detailed instructions on simulations and experimental implementations. At the same time, it showcases the state-of-the-art in terms of detection sensitivity for characterizing mid-infrared waves.

This book introduces the wider field of functional nanomaterials sciences, with a strong emphasis on semiconductor photonics. Whether you are studying photonic quantum devices or just interested in semiconductor nanomaterials and their benefits for optoelectronic applications, this book offers you a pedagogical overview of the relevant subjects along with topical reviews. The book discusses different yet complementary studies in the context of ongoing international research efforts, delivering examples from both fundamental and applied research to a broad readership. In addition, a hand-full of useful optical techniques for the characterization of semiconductor quantum structures and materials are addressed. Moreover, nanostructuring methods for the production of low-dimensional systems, which exhibit advantageous properties predominantly due to quantum effects, are summarized. Science and engineering professionals in the interdisciplinary domains of nanotechnology, photonics, materials sciences, and quantum physics can familiarize themselves with selected highlights with eyes towards photonic applications in the fields of two-dimensional materials research, light-matter interactions, and quantum technologies.

This book describes the fundamentals of THz communications, spanning the whole range of applications, propagation and channel models, RF transceiver technology, antennas, baseband techniques, and networking interfaces. The requested data rate in wireless communications will soon reach from 100 Gbit/s up to 1 Tbps necessitating systems with ultra-high bandwidths of several 10s of GHz which are available only above 200 GHz. In the last decade, research at these frequency bands has made significant progress, enabling mature experimental demonstrations of so-called THz communications, which are thus expected to play a vital role in future wireless networks. In addition to chapters by leading experts on the theory, modeling, and implementation of THz communication technology, the book also features the latest experimental results and addresses standardization and regulatory aspects. This book will be of interest to both academic researchers and engineers in the telecommunications industry.

Paperback

This book provides a detailed overview of the most recent advances in the fascinating world of light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and photodetectors (PDs). Chapters in Section 1 discuss the different types and designs of LEDs/OLEDs and their use in light output, color rendering, and more. Chapters in Section 2 examine innovative structures, emerging materials, and physical effects of PDs. This book is a useful resource for students and scientists working in the field of photonics and advanced technologies.

1 Introduction and motivation.- 2 Related works and basic considerations.- 3 Surface profilometry.- 4 Polymer characterization.- 5 Thin-film characterization.- 6 Conclusion.

Semiconductor quantum optics is on the verge of moving from the lab to real world applications. When stepping from basic research to new technologies, device engineers will need new simulation tools for the design and optimization of quantum light sources, which combine classical device physics with cavity quantum electrodynamics. This thesis aims to provide a holistic description of single-photon emitting diodes by bridging the gap between microscopic and macroscopic modeling approaches. The central result is a novel hybrid quantum-classical model system that self-consistently couples semi-classical carrier transport theory with open quantum many-body systems. This allows for a comprehensive description of quantum light emitting diodes on multiple scales: It enables the calculation of the quantum optical figures of merit together with the simulation of the spatially resolved current flow in complex, multi-dimensional semiconductor device geometries out of one box. The hybrid system isshown to be consistent with fundamental laws of (non-)equilibrium thermodynamics and is demonstrated by numerical simulations of realistic devices.

Achieve the Best Camera Design: Up-to-Date Information on MCMsMiniature camera modules (MCMs), such as webcams, have rapidly become ubiquitous in our day-to-day devices, from mobile phones to interactive TV systems. MCMs--or "smart" cameras--can zoom, adjust their frame rate automatically with illumination change, focus at different distances, compensate for hand shake, and transform captured images. With contributions from academics and field engineers, Smart Mini-Cameras discusses the structure, operation principles, applications, and future trends of miniature mobile cameras. It compares this technology with traditional digital still cameras and explains the specific requirements of MCM components (imposed by the size or type of application) in terms of optical design, image sensor, and functionalities. The book describes the implementation of several active functionalities, including liquid crystal auto focus (AF) and optical image stabilization (OIS). It also explores how new technologies, such as the curved detector and transforming optics, are stimulating novel trends, including a miniature panoramic lens on mobile phones.By providing you with an understanding of the components and performance tradeoffs of MCMs, this book will help you achieve the best camera design. It also answers frequently asked questions, such as the importance of the number of megapixels in a mobile phone camera and the value of AF and OIS features.