Laserfysik

This book analyzes the development of space light-fiber coupling research, highlights its importance, examines the underlying theory and key problems, and elaborates on methods to improve the space light-fiber coupling efficiency. Starting from the basic theory of electromagnetic field, the transmission characteristics of light in optical fibers are expounded, and the coupling characteristics of optical signals of different modes are investigated. The spatial light-fiber coupling techniques such as mode conversion method, lens coupling method, and wavefront distortion correction method are discussed in detail, and the key technologies involved are verified by experiments. This book is suitable for the vast majority of engineering and technical personnel and teachers in colleges and institutions who are engaged in wireless optical communication. It can also be used to train senior undergraduates and graduate students in relevant fields.

The 3rd edition of this textbook offers clear explanations of optical spectroscopic phenomena and shows how spectroscopic techniques are used in modern chemistry, biochemistry and biophysics.Topics included are: electronic and vibrational absorption fluorescence symmetry operations and normal-mode calculations electron transfer from excited moleculesenergy transferexciton interactions electronic and vibrational circular dichroismcoherence and dephasingultrafast pump-probe and photon-echo spectroscopy single-molecule and fluorescence-correlation spectroscopyRaman scatteringmultiphoton absorption quantum optics and non-linear opticsentropy changes during photoexcitationelectronic and vibrational Stark effects studies of fast processes in single moleculestwo-dimensional electronic and vibrational spectroscopyThis revised and updated edition provides expanded discussions of laser spectroscopy, crystal symmetry, birefringence, non-linear optics, solar cells and light-emitting diodes. The explanations are sufficiently thorough and detailed to be useful for researchers, graduate students and advanced undergraduates in chemistry, biochemistry and biophysics. They are based on time-dependent quantum mechanics, but are developed from first principles so that they can be understood by readers with little prior training in the field. Additional topics and highlights are presented in special boxes in the text. The book is richly illustrated with color figures throughout. Each chapter ends with a section of questions for self-examination.

This book highlights the fundamentals and latest progresses in the research and applications of laser shock peening (LSP). As a novel technology for surface treatment, LSP greatly improves the resistance of metallic materials to fatigue and corrosion. The book presents the mechanisms, techniques, and applications of LSP in a systematic way. It discusses a series of new progresses in fatigue performance improvement of metal parts with LSP. It also introduces lasers, equipment, and techniques of newly developed industry LSP, with a detailed description of the novel LSP blisk. The book demonstrates in details numerical analysis and simulation techniques and illustrates process stability control, quality control, and analysis determination techniques. It is a valuable reference for scientists, engineers, and students in the fields of laser science, materials science, astronautics, and aeronautics who seek to understand, develop, and optimize LSP processes.

This thesis presents the first successful realization of a compact, low-noise, and few-cycle light source in the mid-infrared wavelength region. By developing the technology of pumping femtosecond chromium-doped II-VI laser oscillators directly with the emission of broad-stripe single-emitter laser diodes, coherent light was generated with exceptionally low amplitude noise ¿ crucial for numerous applications including spectroscopy at high sensitivities. Other key parameters of the oscillator's output, such as pulse duration and output power, matched and even surpassed previous state-of-the-art systems. As a demonstration of its unique capabilities, the oscillator's powerful output was used to drive ¿ without further amplification ¿ the nonlinear generation of coherent mid-infrared light spanning multiple octaves. The resulting table-top system uniquely combines high brilliance and ultrabroad spectral bandwidth in the important mid-infrared spectral range.The rapid development of this technology is comprehensively and lucidly documented in this PhD thesis. Together with a thorough review of literature and applications, and an extensive analysis of the theoretical foundations behind ultrafast laser oscillators, the thesis will serve as a valuable reference for the construction of a new generation of mid-infrared light sources.

This book focuses on the key technologies supporting orbital-angular-momentum multiplexing communication: generation, transmission, detection, and application of vortex beams. A series of methods for generating vortex beams are described and compared in detail. Laguerre-Gaussian and Bessel-Gaussian beams are taken as examples to introduce the transport properties of vortex beams in atmospheric turbulence. The authors show that superposition of vortex beam state, interference, diffraction, and grating can realize the detection of the topological charge of vortex beams. The authors also introduce the application of vortex beams in optical communication and the transmission characteristics of partially coherent vortex beams in atmospheric turbulence. Finally, the authors describe vortex beam information exchange and channel reconstruction.

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 viability of 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 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 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 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.

The increasing prevalence of nanotechnologies has led to the birth of "nanoelectromagnetics," a novel applied science related to the interaction of electromagnetic radiation with quantum mechanical low-dimensional systems. This book provides an overview of the latest advances in nanoelectromagnetics, and presents contributions from an interdisciplinary community of scientists and technologists involved in this research topic. The aspects covered here range from the synthesis of nanostructures and nanocomposites to their characterization, and from the design of devices and systems to their fabrication. The book also focuses on the novel frontier of terahertz technology, which has been expanded by the impressive strides made in nanotechnology, and presents a comprehensive overview of the: - synthesis of various nanostructured materials; - study of their electrical and optical properties; - use of nano-sized elements and nanostructures as building blocks for devices; - design and fabrication of nanotechnology devices operating in the THz, IR and optical range. The book introduces the reader to materials like nanocomposites, graphene nanoplatelets, carbon nanotubes, metal nanotubes, and silicon nanostructures; to devices like photonic crystals, microcavities, antennas, and interconnects; and to applications like sensing and imaging, with a special emphasis on the THz frequency range.

Die Grundlagen der Laserphysik werden im Rahmen elementarer theoretischer Modelle aus der klassischen Elektrodynamik und der Quantenmechanik dargestellt. Dabei soll ein detailliertes Verstandnis des Prinzips des Lasers, der Eigenschaften des Laserlichtes und der Wechselwirkung von Laserstrahlung mit Materie vermittelt werden. Schwerpunkte bilden die makroskopische Behandlung der Lichtausbreitung in Medien und in Laserresonatoren, die Emission und Absorption von Licht durch Atome im Rahmen der Einsteinschen Theorie, der semiklassischen Lasertheorie und der Quantentheorie des Strahlungsfeldes, die Theorie des Einmodenlasers, sowie die Grundlagen der Koharenzeigenschaften des Lichtes. Erganzende Darstellungen zur Resonanzabsorption, zum Kramers-Henneberger-Bezugssystem, zu Volkov- und koharenten Zustanden in zeitabhangigen elektrischen Feldern und zur relativistischen Mechanik einer Ladung im Laserfeld vermitteln Grundlagen aus dem Bereich der Physik starker Laserfelder.

This volume brings together internationally-leading experimental materials scientists and theoreticians in the field of ultrfast science.