Lasers and Optoelectronics Fundamentals, Devices and Applications

With emphasis on the physical and engineering principles, this book provides a comprehensive and highly accessible treatment of modern lasers and optoelectronics. Divided into four parts, it explains laser fundamentals, types of lasers, laser electronics & optoelectronics, and laser applications, covering each of the topics in their entirety, from basic fundamentals to advanced concepts.

Key features include:

• exploration of technological and application-related aspects of lasers and optoelectronics, detailing both existing and emerging applications in industry, medical diagnostics and therapeutics, scientific studies and Defence.
• simple explanation of the concepts and essential information on electronics and circuitry related to laser systems
• illustration of numerous solved and unsolved problems, practical examples, chapter summaries, self-evaluation exercises, and  a comprehensive list of references for further reading

This volume is a valuable design guide for R&D engineers and scientists engaged in design and development of lasers and optoelectronics systems, and technicians in their operation and maintenance. The tutorial approach serves as a useful reference for under-graduate and graduate students of lasers and optoelectronics, also PhD students in electronics, optoelectronics and physics.

Part I LASER FUNDAMENTALS 1

1 Laser Basics 3

1.1 Introduction 3

1.2 Laser Operation 3

1.3 Rules of Quantum Mechanics 3

1.4 Absorption, Spontaneous Emission and Stimulated Emission 4

1.5 Population Inversion 10

1.6 Two-, Three- and Four-Level Laser Systems 11

1.7 Gain of Laser Medium 16

1.8 Laser Resonator 17

1.9 Longitudinal and Transverse Modes 18

1.10 Types of Laser Resonators 21

1.11 Pumping Mechanisms 23

1.12 Summary 29

2 Laser Characteristics 34

2.1 Introduction 34

2.2 Laser Characteristics 34

2.3 Important Laser Parameters 41

2.4 Measurement of Laser Parameters 49

2.5 Laser Beam Diagnostic Equipment 56

2.6 Summary 59

Part II TYPES OF LASERS 65

3 Solid-state Lasers 67

3.1 Introduction: Types of Laser 67

3.2 Importance of Host Material 67

3.3 Operational Modes 68

3.4 Ruby Lasers 76

3.5 Neodymium-doped Lasers 78

3.6 Erbium-doped Lasers 85

3.7 Vibronic Lasers 88

3.8 Colour Centre Lasers 90

3.9 Fibre Lasers 91

3.10 Summary 101

4 Gas Lasers 105

4.1 Introduction to Gas Lasers 105

4.2 Helium-neon Lasers 107

4.3 Carbon Dioxide Lasers 111

4.4 Metal Vapour Lasers 115

4.5 Rare Gas Ion Lasers 118

4.6 Excimer Lasers 120

4.7 Chemical Lasers 121

4.8 Carbon Dioxide Gas Dynamic Lasers 125

4.9 Dye Laser 125

4.10 Free-electron Lasers 127

4.11 X-Ray Lasers 129

4.12 Summary 129

5 Semiconductor Lasers 132

5.1 Introduction 132

5.2 Operational Basics 132

5.3 Semiconductor Laser Materials 135

5.4 Types of Semiconductor Lasers 136

5.5 Characteristic Parameters 148

5.6 Gain- and Index-guided Diode Lasers 152

5.7 Handling Semiconductor Diode Lasers 152

5.8 Semiconductor Diode Lasers: Application Areas 153

5.9 Summary 154

Part III LASER ELECTRONICS AND OPTOELECTRONICS 159

6 Building Blocks of Laser Electronics 161

6.1 Introduction 161

6.2 Linear Power Supplies 161

6.3 Switched-mode Power Supplies 173

6.4 Constant Current Sources 186

6.5 Integrated-circuit Timer Circuits 191

6.6 Current-to-voltage Converter 197

6.7 Peak Detector 199

6.8 High-voltage Trigger Circuit 200

6.9 Summary 202

7 Solid-state Laser Electronics 208

7.1 Introduction 208

7.2 Spectrum of Laser Electronics 208

7.3 Electronics for Solid-state Lasers 213

7.4 Electronics for Pulsed Solid-state Lasers 214

7.5 Electronics for CW Solid-state Lasers 233

7.6 Solid-state Laser Designators and Rangefinders 237

7.7 Summary 238

8 Gas Laser Electronics 242

8.1 Introduction 242

8.2 Gas Discharge Characteristics 242

8.3 Gas Laser Power Supplies 242

8.4 Helium-Neon Laser Power Supply 244

8.5 Carbon Dioxide Laser Power Supplies 257

8.6 Power Supplies for Metal Vapour Lasers 260

8.7 Power Supplies for Excimer Lasers 261

8.8 Power Supplies for Ion Lasers 262

8.9 Frequency Stabilization of Gas Lasers 263

8.10 Summary 267

9 Laser Diode Electronics 271

9.1 Introduction 271

9.2 Laser Diode Protection 271

9.3 Operational Modes 276

9.4 Laser Diode Driver Circuits 278

9.5 Laser Diode Temperature Control 291

9.6 Summary 308

10 Optoelectronic Devices and Circuits 315

10.1 Introduction 315

10.2 Classification of Photosensors 315

10.3 Radiometry and Photometry 316

10.4 Characteristic Parameters 318

10.5 Photoconductors 324

10.6 Photodiodes 329

10.7 Phototransistors 340

10.8 Photo- FET, SCR and TRIAC 343

10.9 Photoemissive Sensors 345

10.10 Thermal Sensors 347

10.11 Displays 349

10.12 Light-emitting Diodes 351

10.13 Liquid-crystal Displays 356

10.14 Cathode Ray Tube Displays 361

10.15 Emerging Display Technologies 362

10.16 Optocouplers 363

10.17 Summary 370

Part IV LASER APPLICATIONS 379

11 Lasers in Industry 381

11.1 Introduction 381

11.2 Material-processing Applications 381

11.3 Laser Cutting 385

11.4 Laser Welding 390

11.5 Laser Drilling 393

11.6 Laser Marking and Engraving 396

11.7 Laser Micromachining 401

11.8 Photolithography 407

11.9 Rapid Manufacturing 411

11.10 Lasers in Printing 414

11.11 Summary 418

12 Lasers in Medicine 422

12.1 Introduction 422

12.2 Light–tissue Interaction 422

12.3 Laser Diagnostics 430

12.4 Therapeutic Techniques: Application Areas 442

12.5 Ophthalmology 443

12.6 Dermatology 449

12.7 Laser Dentistry 453

12.8 Vascular Surgery 455

12.9 Photodynamic Therapy 456

12.10 Thermal Therapy 459

12.11 Summary 460

13 Lasers in Science and Technology 466

13.1 Introduction 466

13.2 Optical Metrology 466

13.3 Laser Velocimetry 478

13.4 Laser Vibrometry 482

13.5 Electronic Speckle Pattern Interferometry 484

13.6 Satellite Laser Ranging 490

13.7 Lasers in Astronomy 494

13.8 Holography 496

13.9 Summary 503

14 Military Applications: Laser Instrumentation 508

14.1 Introduction 508

14.2 Military Applications of Lasers 508

14.3 Laser-based Instrumentation 512

14.4 Guided Munitions 532

14.5 Laser Communication 556

14.6 Summary 561

15 Military Applications: Directed-energy Laser Systems 566

15.1 Introduction 566

15.2 Laser Technology for Low-intensity Conflict (LIC) Applications 566

15.3 Electro-optic Countermeasures 580

15.4 Directed-energy Laser Weapons 585

15.5 Summary 592

Review Questions 595

Self-evaluation Exercise 596

Bibliography 598

Appendix A: Laser Safety 597

Index 603

Dr. Anil K. Maini is presently Director of Laser science and technology centre, Delhi, a premier R&D Laser Laboratory of Defence Research and Development Organization under Ministry of Defence, Govt. of India. He has more than 35 years of R&D experience as a Scientist, Team Leader, Project Director and Director in diverse disciplines related to Electronics, Lasers and Optoelectronics technologies and systems. His contributions have led to number of innovations in the development of different types of Electronics systems, Optronic sensors and Directed energy laser systems for Indian Defence forces. The key products and technologies developed under his guidance include Power Electronics Systems, family of Laser Dazzling Systems for Homeland security applications, Laser Systems for Electro Optic Counter Measures (EOCM) applications and Optoelectronic Simulators & Sensors for electro optically guided precision strike munitions.

Dr. Anil K. Maini is Life Fellow of Institution of Electronics and Telecommunication Engineers (IETE) and a senior life member of Indian Laser Association. He has written extensively on a wide range of subjects in Electronics and Optoelectronics. He has authored and co-authored twelve books, 6 of the twelve books being international publications. He has delivered numerous invited talks at various universities and research centres. He has worked with several international universities under different collaborative research programmes. He has to his credit five patents and more than 125 publications in National and International journals.