In a very comprehensive way this book covers all aspects of high power diode laser technology for materials processing. Basics as well as new application oriented results obtained in a government funded national German research project are described in detail. Along the technological chain after a short introduction in the second chapter diode laser bar technology is discussed regarding structure, manufacturing technology and metrology. The third chapter illuminates all aspects of mounting and cooling, whereas chapter four gives wide spanning details on beam forming, beam guiding and beam combination, which are essential topics for incoherently coupled multi-emitter based high power diode lasers. Metrology, standards and safety aspects are the theme of chapter five. As an outcome of all the knowledge from chapter two to four various system configurations of high power diode lasers are described in chapter six; not only systems focussed on best available beam quality but especially also so called "modular" set-ups are considered, where assemblies adapted to special applications are chosen. Finally, a wide field of applications, performed with the systems described in chapter six is described in chapter seven.

Autorentext

Poprawe: University Professor with simultaneous responsibility for an application oriented Fraunhofer Institute (ILT, Aachen); The every day business is defined between research, teaching on the University level and Innovation for German, European and global companies.

Loosen: University professor and deputy chair of the Fraunhofer-Institute ILT-Aachen

Bachmann: Product Manager for High Power Diode Lasers at ROFIN-SINAR Laser GmbH, a major manufacturer of laser sources for industrial manufacturing and also directing national government funded R&D projects related to diode laser technology.

Klappentext

This book summarizes a five year research project, as well as subsequent results regarding high power diode laser systems and their application in materials processing. The text explores the entire chain of technology, from the semiconductor technology, through cooling mounting and assembly, beam shaping and system technology, to applications in the processing of such materials as metals and polymers. Includes theoretical models, a range of important parameters and practical tips.

Inhalt

1Motivation and introduction 2High power diode laser technlogy and characteristics 2.1Principles of diode operation 2.2Manufacturing technology 2.3Chip characterization methods and operation 2.4Broad area emitters and arrays 2.5High brightness emitters and arrays 3Packaging of diode laser bars 3.1General aspects 3.2Mounting of diode laser bars 3.3Cooling 3.3.1Introduction 3.3.2 Conduction cooling 3.3.3Micro-channel heatsinks 3.3.4Heatspreaders 3.4Expansion-matched packages 3.5Mounting of micro-optics 4Stacking and incoherent superposition 4.1 Introduction and Survey 4.2 Beam collimation 4.3 Techniques for Beam Combination 4.4 Stacking Techniques 4.5 Beam symmetrization and fiber coupling 4.6 Beam-Quality limits and comparison to coherent coupling 5 Laser systems: beam characteristics, metrology and standards 5.1 Introdiuction 5.2 Theoretical background of beam propagation 5.2.1 Preliminaries 5.2.2 Temporal integration, coherence 5.2.3 Wigner distribution 5.2.4 Propagation of the Wigner distribution through linear optical systems 5.3 Density distribution 5.3.1 Power density distribution in the far field 5.3.2 Width of a power density distribution in a transverse plane 5.4 Propagation of the beam width 5.4.1 Theoretical background 5.4.2 Beam classification 5.4.3 Propagation of the beam width of stigmatic and simple astigmatic beams 5.5. Measurement of the beam power 5.6 Measurement of the power density distribution and the beam propagation ratio, M² 5.6.1 Camera systems 5.6.2 Mechanical scanning devices 5.6.3 Measuring beam caustics 5.6.4 Power density in the far field measurement 5.6.5 Evaluating the widths of ameasured power density distribution 5.6.6 Determination of the beam propagation ration, M² 5.7 Beam positional stability 5.8 Wavefront of a laser 5.9 Lifetime 5.10 Table of international standards related to laser metrology 5.11 References 6 Diode laser systems 6.1 Introduction 6.2 Multi purpose laser systems 6.2.1 Optical cutting plotter with 100 W 6.2.2 Free space propagation systems in the kW range 6.2.3 Fibre coupled system in the kW range 6.2.4 High brightness system with 100 W 6.2.5 High brightness kW system 6.3 Modular diode laser systems 6.3.1 Soldering laser, integrated into a gripping tool - pick and join 6.3.2 Individually addressable intensity line 6.3.3 Line modules for contour adapted plastics welding 6.3.4 Diode laser line cutter 6.3.5 Annular diode laser tool 6.3.6 Process controlling modular diode laser system for transformation hardening 6.3.7 Ring shaped laser for laser assisted machining 6.4 List of symbols 6.5 References 7 Applications 7.1 Joining technologies 7.1.1 Introduction 7.1.2 Metal welding 7.1.3 Brazing 7.1.4 Soldering 7.1.5 Laser Beam Welding of Thermoplastics 7.1.6 References 7.2 Cutting and laser assisted machining technologies 7.2.1 Introduction 7.2.2 Precision cutting with the optical cutting plotter 7.2.3 Single-shot cutting-to-length 7.2.4 Oxygen cutting with annular beam 7.2.5 Laser asisted machining 7.3 Surface treatment 7.3.1 Introduction 7.3.2 Hardening 7.3.2.1 Process principles and equipment 7.3.2.1.1 Differences between / principles of hardening and remelting 7.3.2.1.2 Absorption depending on angle of incidence, material, surface roughness,