Handbook of Laser Technology and Applications, Volume 3: Laser Applications: Material Processing and Spectroscopy

Cover
Half Title
Series Page
Title Page
Copyright Page
Table of Contents
Preface
Editors
Contributors
1. Laser Material Processing: Section Introduction
2. Laser Welding
	2.1 Introduction
	2.2 What Are the Basic Mechanisms for Laser Welding?
		2.2.1 Light–matter Interaction
			2.2.1.1 Laser Energy Is Absorbed by the Material
			2.2.1.2 Melt Is Generated
			2.2.1.3 After Cooling
		2.2.2 Continuous and Pulsed Welding
		2.2.3 Laser Sources
		2.2.4 Practical Considerations
			2.2.4.1 Beam Delivery
			2.2.4.2 Gas Shrouding
			2.2.4.3 Filler Materials
			2.2.4.4 Defects
	2.3 Why Use Laser Welding?
	2.4 What Is Being Done to Ruggedize the Process and Expand Its Implementation?
		2.4.1 Dissimilar Materials
			2.4.1.1 Metal–metal Welding
			2.4.1.2 Dissimilar Materials
		2.4.2 Plastics and Transmissive Materials
		2.4.3 Micro-welding
		2.4.4 Process Developments
			2.4.4.1 Hybrid Processing
			2.4.4.2 Melt Pool Manipulation
			2.4.4.3 Short Wavelength
			2.4.4.4 Short Pulse
			2.4.4.5 Multiple Beams
			2.4.4.6 Melt Pool Support
			2.4.4.7 Aluminium to Steel
		2.4.5 Implementations
			2.4.5.1 Remote Laser Welding
			2.4.5.2 Process Set-up and Diagnostics
	2.5 Future Opportunities
	References
3. High-Power Laser Cutting
	3.1 The Basics of the Laser Cutting Process
		3.1.1 Introduction
		3.1.2 Why Use Laser Cutting?
		3.1.3 Types of High-power Laser Cutting Machines
			3.1.3.1 Three-dimensional Laser Cutting
		3.1.4 Differences between CO[sub(2)] and Fibre Laser Cutting
			3.1.4.1 General
			3.1.4.2 Cutting Speeds
			3.1.4.3 Cut Quality
			3.1.4.4 Laser Absorption in the Cutting Zone
	3.2 How Lasers Cut Different Materials
		3.2.1 General Notes
		3.2.2 Cutting Stainless Steels
		3.2.3 Cutting Mild and Carbon Steels
			3.2.3.1 Cutting Mild Steel with Oxygen
			3.2.3.2 Cutting Mild Steel with Nitrogen
		3.2.4 Cutting Alloy Steels
		3.2.5 Cutting Non-ferrous Metals
			3.2.5.1 Aluminium and Copper Alloys
			3.2.5.2 Titanium Alloys
			3.2.5.3 Nickel Alloys
			3.2.5.4 Other Alloys
		3.2.6 Cutting Non-metals with CO[sub(2)] Lasers
			3.2.6.1 General Notes
			3.2.6.2 Polymers
			3.2.6.3 Other Non-metals
	3.3 Cutting Speeds
		3.3.1 Mild and Carbon Steels
		3.3.2 Stainless Steels
		3.3.3 Aluminium Alloys
		3.3.4 Non-metals – CO[sub(2)] Lasers Only
	Acknowledgements
4. Laser Marking
	4.1 Introduction
	4.2 Laser-marking Equipment
		4.2.1 CO[sub(2)] Lasers (10.6 μm IR Wavelength)
		4.2.2 Excimer Lasers
		4.2.3 YAG Lasers
	4.3 Materials
		4.3.1 Plastics
		4.3.2 Glass and Ceramics
		4.3.3 Metals
		4.3.4 Semiconductors
	4.4 Competitors for Laser Marking
	4.5 Case Study: Decorative Marking of Plastics
	References
5. Laser Micromachining
	5.1 Introduction
	5.2 Basics
		5.2.1 Energy Transfer
		5.2.2 Absorption of Light
		5.2.3 Heat Transfer for Long (Nanosecond) Pulses
			5.2.3.1 Heat Diffusion Equation
			5.2.3.2 Point Source in Infinite Homogeneous 3D Body
			5.2.3.3 Linear Heat Conduction
			5.2.3.4 Enthalpy Model
		5.2.4 Heat Transfer for Ultra-short Pulses
			5.2.4.1 Two-temperature Model
			5.2.4.2 Metals
			5.2.4.3 Dielectrics and Semiconductors
		5.2.5 Heat Accumulation
	5.3 Optimized Material Removal
		5.3.1 Problem
		5.3.2 Ablation Efficiency
			5.3.2.1 Top Hat Intensity Distribution
			5.3.2.2 Gaussian Beam
		5.3.3 Specific Removal Rate
		5.3.4 Consequences from the Model
		5.3.5 Incubation
		5.3.6 Influence of the Pulse Duration
		5.3.7 Influence on the Machining Quality
			5.3.7.1 Metals
			5.3.7.2 Semiconductors: Silicon and Germanium
	5.4 Power Scale-up for Surface Structuring: Demands, Solutions and Limiting Factors
		5.4.1 Surface Structuring
		5.4.2 Marking Speed and Power Scale-up
		5.4.3 Limiting Factors
			5.4.3.1 Heat Accumulation
			5.4.3.2 Plasma and Particle Shielding
		5.4.4 Pulse Bursts
		5.4.5 Alternative Approaches
	5.5 Summary and Future Challenges
	References
6. Rapid Manufacturing
	6.1 Basic Principles
	6.2 Main Technologies and System Requirements
		6.2.1 Control of Material Composition Changes
	6.3 Case Study
	6.4 Future Trends
	References
7. Laser Printing
	7.1 Introduction
	7.2 Multiphoton Polymerization
	7.3 Stimulated Emission Depletion for Multiphoton Lithography (STED)
	7.4 Laser-induced Forward Transfer
	7.5 Conclusions
	References
8. 3D Printing and Additive Manufacturing
	8.1 Introduction
	8.2 Stereolithography
	8.3 Selective Laser Sintering (SLS) Technology
	8.4 Microscale 3D Printing Techniques
		8.4.1 Projection Micro-stereolithography
		8.4.2 Multiphoton Lithography
			8.4.2.1 Multiphoton Polymerization Technique
			8.4.2.2 Sequential and Simultaneous Two-photon Absorption (TPA)
			8.4.2.3 Experimental Set-up
			8.4.2.4 Materials for Laser Polymerization
			8.4.2.5 Applications
	References
9. Photolithography
	9.1 Basic Principles
	9.2 System Requirements
	9.3 Case Study (KrF Excimer Laser Lithography)
	9.4 Future Trends
	Bibliography
10. Pulsed Laser Deposition of Thin Films
	10.1 History and Background
	10.2 Operation of PLD and Process Steps
		10.2.1 Laser–Material Interaction
		10.2.2 Material Transport
		10.2.3 Nucleation and Growth
	10.3 Materials Grown by Using PLD
		10.3.1 Metals and Alloys
		10.3.2 Oxides
			10.3.2.1 Ferroelectric, Multiferroics, and Piezoelectric Oxides
			10.3.2.2 Superconducting Oxides
			10.3.2.3 Transparent Conducting Oxides
		10.3.3 Nitrides
		10.3.4 Transition Metal Dichalcogenides
		10.3.5 Diamond-like Carbon
		10.3.6 Polymers
		10.3.7 Biomaterials
		10.3.8 Other Materials
	10.4 Advantages and Disadvantages of PLD
	10.5 Summary
	References
11. Surface Micro- and Nano-structuring on Metals with Femtosecond Lasers
	11.1 Introduction
	11.2 Basic Principles
	11.3 Femtosecond Laser Nano-/Microstructuring
		11.3.1 Irregular Nanostructures
		11.3.2 Femtosecond Laser-induced 1D Periodic Subwavelength Structures
		11.3.3 Femtosecond Laser-Induced 2D Periodic Subwavelength Structures
	11.4 Conclusion
	References
12. Laser Ablation in Liquids for Nanoparticle Generation and Modification
	12.1 Introduction
	12.2 Background of LP-PLA of a Solid Target at the Solid–Liquid Interface
		12.2.1 Nucleation and Growth of NPs from Laser-produced Plasmas Confined in Liquid
			12.2.1.1 Early Stage
			12.2.1.2 Intermediate Stage
			12.2.1.3 Later Stage
	12.3 Effects of Different Experimental Parameters on the Dynamics of Laser Ablation
	12.4 Cavitation Bubble Formation and Related Effects
	12.5 Non-reactive LP-PLA of Solids for the Generation of Elemental Nanoparticles
	12.6 Reactive Pulsed Laser Ablation for the Generation of Metal Compound Nanoparticles
	12.7 Laser Ablation of Suspended Particles in Liquids
	12.8 Conclusions
	References
13. Laser-Induced Forward Transfer
	13.1 Introduction
		13.1.1 LIFT with a Sacrificial Layer
		13.1.2 LIFT of Liquids
	13.2 LIFT in Science: Examples of Materials and Devices Transferred by LIFT
	13.3 LIFT in Industry
	13.4 Conclusions and Future Directions
	Acknowledgements
	References
14. Laser Pyrolysis
	14.1 Introduction
	14.2 Experimental Set-up
	14.3 Control Parameters
	14.4 Typical Operating Procedures for Laser Pyrolysis
	14.5 Examples of NPs Synthesized by Laser Pyrolysis
		14.5.1 Elemental NPs
		14.5.2 Compound Non-oxide NPs
		14.5.3 Compound Oxide NPs
	14.6 Challenges and Future Work
	14.7 Conclusions
	References
15. Laser Spectroscopy: Section Introduction
16. Laser Raman Spectroscopy: Fundamentals to Applications
	16.1 Raman Scattering
	16.2 Theory of Raman Scattering
		16.2.1 Classical Description of Raman Effect
		16.2.2 Quantum Mechanical Description of Raman Effect
		16.2.3 Instrumentation
	16.3 Other Raman Spectroscopic Techniques
		16.3.1 Surface-Enhanced Raman Scattering
			16.3.1.1 Origin of Enhancement
		16.3.2 Non-linear Raman and Ultrafast Spectroscopy
			16.3.2.1 Theory and Instrumentation of Non-linear Third-Order Processes
			16.3.2.2 Experimental Method
	16.4 Applications of Raman Spectroscopy
		16.4.1 Carbon Characterization Using Raman Spectroscopy
		16.4.2 Applications of SERS
		16.4.3 Raman Spectroscopy in Semiconductors
		16.4.4 Raman Spectroscopy for Pharmaceutical Analysis
	16.5 Raman Spectroscopic Techniques for Non-invasive Depth-Resolved Studies
		16.5.1.1 Spatially Offset Raman Spectroscopy
		16.5.1.2 Universal Multiple-Angle Raman Spectroscopy
		16.5.1.3 Transmission Raman Spectroscopy (TRS)
	16.6 Raman Imaging: From 2D Mapping Towards 3D Imaging
	16.7 Non-linear Spectroscopic Applications
		16.7.1 Photoisomerization of Optically Excited Solvated Trans-stilbene
		16.7.2 Ultrafast Structural Dynamics
		16.7.3 Excited-state Planarization Dynamics of Bis(phenylethnyl)benzene
	16.8 Conclusion and Future Directions
	References
17. Laser Scattering Spectroscopy: Rayleigh Scattering and Dynamic Light Scattering
	17.1 Introduction
	17.2 General Principles of DLS (Photon Correlation Spectroscopy)
	17.3 Consideration of Angular and Concentration Effect on the DLS Measurement
	17.4 Consideration of Uncertainty Sources of the DLS Measurement
	17.5 Consideration of the Size Distribution of Particles Determined by DLS
	17.6 Conclusion
	References
18. Laser-Induced Breakdown Spectroscopy
	18.1 Introduction
	18.2 Application of LIBS
		18.2.1 Determination of Gold Fineness by Laser-induced Breakdown Spectroscopy
		18.2.2 Laser-induced Plasma to Decompose Hydrocarbon Molecules
			18.2.2.1 Medical Application
	References
19. Laser-Induced Fluorescence (LIF) for the Detection of Microbes
	19.1 Introduction
	19.2 Principles of Fluorescence and LIF from Microbes
		19.2.1 Physical Principles and Special Properties in Biological Samples
		19.2.2 Biological Fluorophores
		19.2.3 Basic Fluorescence Behaviour of Microbes
	19.3 Equipment for Laser-Induced Fluorescence
	19.4 Data Analysis
		19.4.1 Classification, Discrimination, Identification
		19.4.2 LIDAR Equation: Application for LIF Stand-off Detection
	19.5 Fields of Application
		19.5.1 Single-Particle Detection (Short Distances)
		19.5.2 Bulk Detection (Short and Long Distances)
			19.5.2.1 LIF Stand-Off Detection of Diluted Microbes
			19.5.2.2 LIF Stand-Off Detection of Atmospheric Aerosols (Fluorescence LIDAR)
	19.6 Summary
	References
20. Harmonic Generation—Materials and Methods
	20.1 Introduction
	20.2 Second-harmonic Generation
		20.2.1 Effective Non-linear Coefficient
		20.2.2 Conversion Efficiency
		20.2.3 Phase-matching
		20.2.4 Phase-matching Bandwidth
		20.2.5 Intra-cavity and Resonant Cavity Second-harmonic Generation
	20.3 Sum and Difference Frequency Mixing
		20.3.1 Theory
		20.3.2 Sum Frequency Mixing
		20.3.3 Difference Frequency Mixing
	20.4 Third- and Higher-harmonic Generation
	20.5 Non-linear Materials for Frequency Conversion
		20.5.1 Birefringent Materials
		20.5.2 Quasi-Phase-matched Materials
		20.5.3 Self-doubling and Summing Materials
	20.6 Frequency Conversion of Particular Lasers
		20.6.1 Nd Lasers
		20.6.2 Ti:sapphire Lasers
		20.6.3 Carbon Dioxide Lasers
	20.7 Developing and Growth Areas
	References
21. Non-linear Optical Properties of Novel Nanomaterials
	21.1 Introduction
		21.1.1 Origin of NLO: Master-Slave Flip Flop
		21.1.2 Maxwell’s Equations and Non-linear Polarization
	21.2 Second-order NLO Properties
		21.2.1 Second Harmonic Generation
		21.2.2 Sum Frequency Generation
		21.2.3 Difference Frequency Generation
		21.2.4 Nanomaterials for Second-Order Non-linear Optics
	21.3 Third-Order Optical Non-linearities
		21.3.1 Non-linear Absorption
			21.3.1.1 Saturable Absorption and Reverse Saturable Absorption
			21.3.1.2 Genuine Multi-photon Absorption
			21.3.1.3 Excited-state Absorption and Free Carrier Absorption
		21.3.2 Non-linear Refraction
			21.3.2.1 Electronic Polarization
			21.3.2.2 Raman-induced Kerr Effect and Photorefractive Effect
			21.3.2.3 Molecular Orientational Effects and Population Redistribution
			21.3.2.4 Electrostriction
			21.3.2.5 Thermo-optic Effects
		21.3.3 Optical Limiting
		21.3.4 Z-scan Experimental Technique
			21.3.4.1 Theory of Open Aperture Z-scan
			21.3.4.2 Wavelength-dependent Non-linear Absorption Coefficient
			21.3.4.3 Theory of Closed Aperture Z-scan
		21.3.5 Third-order NLO Susceptibility and Optical Limiting
		21.3.6 Third-order NLO Materials: Brief Survey
			21.3.6.1 Metal Nanoparticles
			21.3.6.2 Metal Nanocomposites
			21.3.6.3 Perovskite Materials
	21.4 Conclusions
	21.5 Future Scope
	References
22. Lasers in Imaging: Section Introduction
23. Lasers in Microscopy
	23.1 Introduction
	23.2 Basic Principles of Microscopy
		23.2.1 Wide-field and Laser Scanning Microscopy
		23.2.2 Fluorescence Excitation and Emission
		23.2.3 Resolution
		23.2.4 Scattering and Absorption of the Specimen
	23.3 Advanced Techniques in Microscopy
		23.3.1 Two-photon Excitation
		23.3.2 Raman Microscopy
		23.3.3 Coherent Anti-Stokes Raman Scattering (CARS) and Stimulated Raman Scattering (SRS) Microscopy
		23.3.4 Super-resolution Microscopy
			23.3.4.1 Stimulated Emission Depletion (STED)
			23.3.4.2 Single-molecule Localization Microscopy (SMLM)
	23.4 Conclusion and Discussion
	References
24. Laser-based Coherent Diffractive Imaging
	24.1 Introduction
	24.2 Methods
		24.2.1 Plane-Wave CDI
		24.2.2 Fresnel CDI
		24.2.3 Ptychography
	24.3 Algorithms
		24.3.1 Error Reduction
		24.3.2 HIO
		24.3.3 Projector Notation
	24.4 Applications
	24.5 Perspective
	References
25. High-Speed Imaging
	25.1 Properties of Laser Radiation Which Make It Useful for High-speed Imaging
		25.1.1 Short-duration Pulses
		25.1.2 Low Divergence
		25.1.3 Fibre Delivery
		25.1.4 Lightsheets
		25.1.5 Laser Speckle
		25.1.6 High-Brightness Imaging
	25.2 High-speed Camera Technology
		25.2.1 High-speed Film
		25.2.2 Electronic Cameras
	25.3 Choice of Laser
		25.3.1 Illumination Techniques
	25.4 Application Examples
		25.4.1 Time-resolved PIV in Engines
		25.4.2 Agricultural Spray Characterization
		25.4.3 Drug Delivery Sprays
	25.5 Summary
	References
	Further Reading
26. Ultrafast Optical Imaging
	26.1 Introduction
	26.2 Multiple-shot Ultrafast Optical Imaging
		26.2.1 Temporal Scanning
			26.2.1.1 Ultrashort Probing
			26.2.1.2 Ultrafast Gating
		26.2.2 Spatial Scanning
			26.2.2.1 Point Scanning
			26.2.2.2 Line Scanning
	26.3 Single-shot Ultrafast Optical Imaging
		26.3.1 Active Detection
			26.3.1.1 Angle Division
			26.3.1.2 Wavelength Division
			26.3.1.3 Frequency Division
		26.3.2 Passive Detection
			26.3.2.1 Direct Imaging
			26.3.2.2 Computational Reconstruction
	26.4 Summary and Outlook
	References
27. Transient Absorption Microscopy Measurements of Single Nanostructures
	27.1 Introduction
	27.2 Experimental Methods
		27.2.1 Laser Systems for Transient Absorption Microscopy
		27.2.2 Optical Components and Signal Detection
		27.2.3 Signal-to-Noise Considerations
	27.3 Dynamics of Single Nanostructures
	27.4 Summary and Future Directions
	Acknowledgements
	References
Index