Laserfysik

In this dissertation a new process chain for the Additive Manufacturing of Mechatronic Integrated Devices (AMMID) is described, which provides a new way to manufacture 3-dimensional electronic devices based on the selective laser sintering (SLS) process using laser direct structuring (LDS) and metallization. The AMMID process chain meets the rising demand for highly functionalized parts, increasing individualization and shortening development cycles for electronic products.The development for this process chain is based on an extensive literature review that indicates that an SLS-based process chain has great potential to produce 3-dimensional electronic devices with properties and with the future perspective of being suitable for an individualized mass production. The biggest, initial, technical hurdle is an unstable SLS process using a conventional LDS additive. The compound of SLS material and LDS additive was analyzed with DSC, which shows that the additive changes the melting behavior of the polymer by reducing the sintering window. A fine metal powder as an alternative additive affects the sintering window less and enables a stable process. To choose a suitable particle size and content for the metal powder an analytical material model is provided, that predicts the additive particle distribution within the material. This material model deepens the understanding of the activation mechanism during laser activation, provides hands-on information for powder preparation and it is applied for the design of the experiment for the development of the process chain with the new material.Preliminary experiments are conducted along with the insights of the material model, which prove that redeposition is the main activation mechanism during laser activation with fine metal powders. Based on this, the process chain is developed, starting with a determination of a suitable additive content. A suitable material composition of a PA12 powder containing 2 wt.% of a copper powder with a mean particle diameter of 3.5 ?m was identified. With regard to the laser activation, working laser parameters are developed (working parameter set feasible for all used post-process treatments: PRF = 1 kHz, dh = 25 ?m, vs = 25 mm/s, tl = 20ns and P = 1.07 W). In this parameter development it is shown, that only closely located laser spots, enabling interaction of the laser pulses, are capable of activating the surface, while single laser pulses under applied conditions are not. By adding a post-process treatment as additional process step into the process chain, the quality of metallization and the size of design features could be improved. Chemical smoothing resulted in a complete reduction of unwanted metallization on non-activated surfaces. Conductor tracks with the minimal width of 300 ?m could be realized. The process chain could be applied to demonstrator parts such as a drone housing and a PSU panel of an aircraft. Thus, this dissertation has raised the technology readiness level (TRL) from TRL2 to TRL6.Finally, an economic consideration provides insights on the cost structure of parts produced with the AMMID process. A comparison of AMMID and injection molding shows economic viability for small lot sizes, 400 parts in case of the drone housing and 150 parts in case of the PSU panel. Finally, the analysis of the cost structure gives advice which future developments in the process chain have the greatest effect on costs and provides prioritization.

This book presents new frontiers in data communication. To transcend the physical limitations of current optical communication technologies, totally new multiplexing schemes beyond TDM/WDM, novel transmission optical fibers handling well above Pbit/s capacity, and next-generation optical submarine cable systems will need to be developed. The book offers researchers working at the forefront, as well as advanced Ph.D. students in the area of optical fiber communications systems and related fields, an essential guide to state-of-the-art optical transmission technologies. It explores promising new technologies for the exabit era; namely, the three "e;M technologies"e;: multi-level modulation, multi-core fiber, and multi-mode control.

This book presents posits a solution to the current limitations in global connectivity by introducing a global laser/optical communication system using constellation satellites, UAVs, HAPs and Balloons. The author outlines how this will help to satisfy the tremendous increasing demand for data exchange and information between end-users worldwide including in remote locations. The book provides both fundamentals and the advanced technology development in establishing worldwide communication and global connectivity using, (I) All-Optical technology, and (ii) Laser/Optical Communication Constellation Satellites (of different types, sizes and at different orbits), UAVs, HAPs (High Altitude Platforms) and Balloons. The book discusses step-by-step methods to develop a satellite backbone in order to interconnect a number of ground nodes clustered within a few SD-WAN (software-defined networking) in a wide area network (WAN) around the world in order to provide a fully-meshed communication network. This book pertains to anyone in optical communications, telecommunications, and system engineers, as well as technical managers in the aerospace industry and the graduate students, and researchers in academia and research laboratory.Proposed a solution to the limitations in global connectivity through a global laser/optical communication system using constellation satellites, UAVs, HAPs and Balloons;Provides both fundamentals and the advanced technology development in establishing global communication connectivity using optical technology and communication constellation satellites;Includes in-depth coverage of the basics of laser/optical communication constellation satellites.

This volume provides a consolidated reference for the applications of frequency selective surfaces (FSS) technology in different sectors such as wireless communications, smart buildings, microwave and medical industries. It covers all aspects of metamaterial FSS technology starting from theoretical simulation, fabrication and measurement all the way to actual hardware implementation. Also included are in-depth discussions on the design methodologies of metamaterial FSS structures and their practical implementation in devices and components. It will be of interest to researchers and engineers working on developing metamaterial-FSS technology.

When this publisher offered me the opportunity to \\Tite a book, some six years ago, I did not hesitate to say yes. I had just spent the last four years of graduate school struggling to understand the physics of strained quantum well lasers, and it seemed to me the whole experience was much more difficult that it should have been. For although many of the results I needed were easy to locate, the underlying physical premises and intervening steps were not. If only I had a book providing the derivations, I could have absorbed them and gone on my way. Such a book lies before you. It provides a unified and self-contained descrip­ tion of the essential physics of strained quantum well lasers, starting from first principles whenever feasible. The presentation I have chosen requires only the standard introductory background in quantum mechanics, solid state physics, and electromagnetics expected of entering graduate students in physics or elec­ trical engineering. A single undergraduate course in each of these subjects should be more than sufficient to follow the text. :'Iore advanced material on quantum mechanics is developed and collected in the first chapter. \Vhen pos­ sible, I have presented the results in a general setting and have later applied them to specific cases of interest. I find this the most satisfying way to ap­ proach the subject, and it has the additional benefit of solving many problems once and for all.

In recent years, we have witnessed a rapid expansion of using super-thin metasurfaces to manipulate light or electromagnetic wave in a subwavelength scale. However, most designs are confined to a passive scheme and monofunctional operation, which hinders considerably the promising applications of the metasurfaces. Specifically, the tunable and multifunctional metasurfaces enable to facilitate switchable functionalities and multiple functionalities which are extremely essential and useful for integrated optics and microwaves, well alleviating aforementioned issues. In this book, we introduce our efforts in exploring the physics principles, design approaches, and numerical and experimental demonstrations on the fascinating functionalities realized. We start by introducing in Chapter 2 the "e;merging"e; scheme in constructing multi-functional metadevices, paying particular attention to its shortcomings issues. Having understood the merits and disadvantages of the "e;merging"e; scheme, we then introduce in Chapter 3 another approach to realize bifunctional metadevices under linearly polarized excitations, working in both reflection and transmission geometries or even in the full space. As a step further, we summarizes our efforts in Chapter 4 on making multifunctional devices under circularly polarized excitations, again including designing principles and devices fabrications/characterizations. Starting from Chapter 5, we turn to introduce our efforts on using the "e;active"e; scheme to construct multifunctional metadevices under linearly polarized wave operation. Chapter 6 further concentrates on how to employ the tunable strategy to achieve helicity/frequency controls of the circularly polarized waves in reflection geometry. We finally conclude this book in Chapter 7 by presenting our perspectives on future directions of metasurfaces and metadevices.

Singlet Oxygen, the lowest electronically excited state of molecular oxygen, is highly reactive and involved in many chemical and biological processes. It is one major mediator during photosensitization, which has been used by mankind since ancient times, even though the mechanisms behind it were understood only about half a century ago. The combination of high reactivity and very long natural lifetime allows for direct optical detection of singlet oxygen and its interactions using its characteristic phosphorescence at around 1270 nm. Since this emission is very weak, optical detection was technically very challenging for a long time. Therefore, even today, most laboratories only exploit the high reactivity to observe the interaction with sensor molecules, rather than singlet oxygen emission itself. However, in recent years highly sensitive optical detection was developed, the authors being major contributors. This book is dedicated to the detection of singlet oxygen, discussing possibilities, pitfalls and limits of the various methods with a special focus on time-resolved phosphorescence and the kinetics of singlet oxygen generation and decay including involved and related processes, discussing investigated systems with various complexity from solutions over in vitro to in vivo. The long-standing paradigm that singlet oxygen phosphorescence is a benchmark for detection systems rather than an option for process observation is still ubiquitous and this book hopes to contribute in overcoming this still prevailing bias.

Over the last two decades, Atomic Force Microscopy (AFM) has undoubtedly had a considerable impact in unraveling the structures and dynamics of microbial surfaces with nanometer resolution, and under physiological conditions. Moreover, the continuous innovations in AFM-based modalities as well as the combination of AFM with modern optical techniques, such as confocal fluorescence microscopy or Raman spectroscopy, increased the diversity and volume of data that can be acquired in an experiment. It is evident that these combinations provide new ways to investigate a broad spectrum of microbiological processes at the level of single cells. In this book, I have endeavored to highlight the wealth of AFM-based modalities that have been implemented over the recent years leading to the multiparametric and multifunctional characterization of, specifically, bacterial surfaces. Examples include the real-time imaging of the nanoscale organization of cell walls, the quantification of subcellular chemical heterogeneities, the mapping and functional analysis of individual cell wall constituents, and the probing of the nanomechanical properties of living bacteria. It is expected that in the near future more AFM-based modalities and complementary techniques will be combined into single experiments to address pertinent problems and challenges in microbial research. Such improvements may make it possible to address the dynamic nature of many more microbial cell surfaces and their constituents, including the restructuring of cellular membranes, pores and transporters, signaling of cell membrane receptors, and formation of cell-adhesion complexes. Ultimately, manifold discoveries and engineering possibilities will materialize as multiparametric tools allow systems of increasing complexity to be probed and manipulated.

Atomically precise metal nanocluster research has emerged as a new frontier. This book serves as an introduction to metal nanoclusters protected by ligands. The authors have summarized the synthesis principles and methods, the characterization methods and new physicochemical properties, and some potential applications. By pursuing atomic precision, such nanocluster materials provide unprecedented opportunities for establishing precise relationships between the atomic-level structures and the properties. The book should be accessible to senior undergraduate and graduate students, researchers in various fields (e.g., chemistry, physics, materials, biomedicine, and engineering), R&D scientists, and science policy makers.

Introduction to Photonic and Phononic Crystals and Metamaterials, by Arthur R. McGurn, presents a study of the fundamental properties of optical and acoustic materials which have been of recent interest in nanoscience and device technology. The level of the presentations is appropriate for advanced undergraduates, beginning graduate students, and researchers not directly involved in the field. References are given to guide the reader to more advanced study in these fields.Discussions of the physics of photonic and phononic crystals focus on the transmission properties of optical and acoustic radiation arising from their diffractive interaction in these engineered materials. The frequency transmission and non-transmission bands of radiation are explained in terms of the symmetry properties of the photonic and phononic artificial crystal structures. Basic applications of these properties to a variety of their technological applications are examined.The physics of metamaterials is discussed along with their relationships to the ideas of resonance. Properties of negative index of refraction, perfect lens, and unusual optical effects the new optics of metamaterial media makes available are examined. Related effects in acoustics are also covered.Basic principles of surface acoustic and electromagnetic waves are explained. These form an introduction to the fundamental ideas of the recently developing fields of plasmonics and surface acoustics.

Machine learning methods are changing the way we design and discover new materials. This book provides an overview of approaches successfully used in addressing materials problems (alloys, ferroelectrics, dielectrics) with a focus on probabilistic methods, such as Gaussian processes, to accurately estimate density functions. The authors, who have extensive experience in this interdisciplinary field, discuss generalizations where more than one competing material property is involved or data with differing degrees of precision/costs or fidelity/expense needs to be considered.

Minimally invasive techniques such as Photodynamic Therapy (PDT) and Photochemical Internalisation (PCI) have for years been under investigation for the treatment of solid cancers. A significant number of the recent research studies have applied PDT and PCI to biological three-dimensional (3D) cancer platforms with many of the studies also involving the use of nanoparticles in order to enhance the efficacy of these light-based therapies. Interest in the employment of 3D cancer platforms has increased considerably due to the ability of the platforms to mimic in vivo models better than the conventional two-dimensional (2D) cultures. Some of the advantages of the 3D cancer systems over their 2D counterparts include improved interaction between cancer cells and the surrounding extracellular matrix (ECM) as well as restricted drug penetration which would allow optimization of treatments prior to undertaking of in vivo studies. The different chapters of this book will discuss photosensitizers and nanoparticles used in PDT and PCI in addition to the applications of these treatments in various 3D cancer models.

This book, Introduction to Optics I: Interaction of Light with Matter, is the first book in a series of four covering the introduction to optics and optical components. The author's targeted goal for this series is to provide clarity for the reader by addressing common difficulties encountered while trying to understand various optics concepts. This first book is organized and written in a way that is easy to follow, and is meant to be an excellent first book on optics, eventually leading the way for further study. Those with technical backgrounds as well as undergraduate students studying optics for the first time can benefit from this book series.The current book includes three chapters on light and its characteristics (Chapter 1), on matter from the standpoint of optics (Chapter 2), and on the interaction of light with matter (Chapter 3). Among the characteristics of light, the ones characterizing its speed, color, and strength are covered. The polarization of light will be covered in the next book of the series, where we discuss optical components. Chapter 2 discusses various atomic and molecular transitions activated by light (optical transitions). Different kinds of natural bulk material media are described: crystalline and amorphous, atomic and molecular, conductive and insulating. Chapter 3 on the interaction of light with matter describes naturally occurring phenomena such as absorption, dispersion, and nonlinear optical interactions. The discussion is provided for the natural bulk optical materials only. The interfaces between various materials will be covered in the next book on optical components.The following three books of the series are planned as follows. In the second book, we will focus on passive optical components such as lenses, mirrors, guided-wave, and polarization optical devices. In the third book, we will discuss laser sources and optical amplifiers. Finally, the fourth book in the series will cover optoelectronic devices, such as semiconductor light sources and detectors.

The merging of metasurface and holography brings about unprecedented opportunities for versatile manipulation of light in terms of both far-field wavefront and near-field profile. In this book, a brief evolving history from surface plasmon polariton holography to metamaterial holography and finally to metasurface holography is introduced at first. Basic physical mechanisms that govern the phase modulation rules behind metasurface holography design are discussed later. Next, extended functionalities such as arbitrary polarization holography, vectorial holography, full-color holography, and hybrid holography achieved in the metasurface platform are presented. Surface wave and metagrating holography that bridges the on-chip surface wave and free-space wave is also introduced. In the end, we envisage practical applications of high-fidelity 3D holographic display, high-secure encryption, and high capacity digital encoding and also indicate remaining challenges based on metasurface holography.

The process of heating and reshaping plastics sheet and film materials has been in use since the beginning of the plastics industry. This process is known as thermoforming. Today this process is used for industrial products including signage, housings, and hot tubs. It also produces much of the packaging in use today including blister packs, egg cartons, and food storage containers. This process has many advantages over other methods of producing these products, but it has some limitations. This book has a twofold purpose. It is designed to be used as a text book for a course on thermoforming. It is also intended to be an application guide for professionals in the field of thermoforming including manufacturing, process and quality engineers, and managers. This book is focused on process application rather than theory. It refers to real products and processes with the intent of understanding the real issues faced in this industry. In addition to materials and processes, part and tool design are covered. Quality control is critical to any operation and this is also covered in this text. Two areas of focus in today's industry include Lean operations and environmental issues. Both of these topics are also included. Table of Contents: Introduction / Plastics Materials / Thermoforming Process Overview / The Forming Process / Part Design Mold / Tool Design / Quality Control Issues / Lean Operations / Environmental Issues