1 Spontaneous and Stimulated Transitions 1
1.1 Introduction 1
1.2 Why'Quantum'Electronics? 1
1.3 Amplification at Optical Frequencies 3
1.3.1 Spontaneous Emission 4
1.3.2 Stimulated Emission 6
1.4 The Relation Between Energy Density and Intensity 7
1.4.1 Stimulated Absorption 10
1.5 Intensity of a Beam of Electromagnetic Radiation in Terms of Photon Flux 11
1.6 Black-Body Radiation 11
1.7 Relation Between the Einstein A and B Coefficients 16
1.8 The Effect of Level Degeneracy 18
1.9 Ratio of Spontaneous and Stimulated Transitions 19
1.10 Problems 20
2 Optical Frequency Amplifiers 22
2.1 Introduction 22
2.2 Homogeneous Line Broadening 22
2.2.1 Natural Broadening 22
2.3 Inhomogeneous Broadening 26
2.3.1 Doppler Broadening 27
2.4 Optical Frequency Amplification with a Homogeneously Broadened Transition 30
2.4.1 The Stimulated Emission Rate in a Homogeneously Broadened System 33
2.5 Optical Frequency Amplification with Inhomogeneous Broadening Included 34
2.6 Optical Frequency Oscillation-Saturation 35
2.6.1 Homogeneous Systems 35
2.6.2 Inhomogeneous Systems 38
2.7 Power Output from a Laser Amplitier 44
2.8 The Electron Oscillator Model of a Radiative Transition 45
2.9 What Are the Physical Significances of x'and x"? 49
2.10 The Classical Oscillator Explanation for Stimulated Emission 52
2.11 Problems 54
References 55
3 Introduction to Two Practical Laser Systems 57
3.1 Introduction 57
3.1.1 The Ruby Laser 57
3.2 The Helium-Neon Laser 63
References 67
4 Passive Optical Resonators 68
4.1 Introduction 68
4.2 Preliminary Consideration of Optical Resonators 68
4.3 Calculation of the Energy Stored in an Optical Resonator 70
4.4 Quality Factor of a Resonator in Terms of the Transmission of its End Reflectors 72
4.5 Fabry-Perot Etalons and Interferometers 73
4.6 Internal Field Strength 79
4.7 Fabry-perot Interferometers as Optical Spectrum Analyzers 81
4.7.1 Example 84
4.8 Problems 86
References 87
5 Optical Resonators Containing Amplifying Media 88
5.1 Introduction 88
5.2 Fabry-Perot Resonator Containing an Amplifying Medium 88
5.2.1 Threshold Population Inversion-Numerical Example 91
5.3 The Oscillation Frequency 92
5.4 Multimode Laser Oscillation 93
5.5 Mode-Beating 99
5.6 The Power Output of a Laser 101
5.7 Optimum Coupling 105
5.8 Problems 106
References 107
6 LaserRadiation 108
6.1 Introduction 108
6.2 Diffraction 108
6.3 Two Parallel Narrow Slits 110
6.4 Single Slit 110
6.5 Two-Dimensional Apertures 111
6.5.1 Circular Aperture 111
6.6 LaserModes 113
6.7 Beam Divergence 117
6.8 Linewidth of Laser Radiation 118
6.9 Coherence Properties 119
6.10 Interference 121
6.11 Problems 124
References 124
7 Control of Laser Oscillators 126
7.1 Introduction 126
7.2 Multimode Operation 126
7.3 Single Longitudinal Mode Operation 127
7 4 Mode-Locking 131
7.5 Methods of Mode-Locking 134
7.5.1 Active Mode-Locking 134
7.6 Pulse Compression 138
References 139
8 Optically Pumped Solid-Stare Lasers 141
8.1 Introduction 141
8.2 Optical Pumping in Three-and Four-Level Lasers 141
8.2.1 Effective Lifetime of the Levels Involved 141
8.2.2 Threshold Inversion in Three-and Four-Level Lasers 142
8.2.3 Quantum Efficiency 143
8.2.4 Pumping Power 143
8.2.5 Threshold Lamp Power 144
8.3 PuIsed Versus CW Operation 144
8.3.1 Threshold for Pulsed Operation of a Ruby Laser 145
8.3.2 Threshold for CW Operation of a Ruby Laser 145
8.4 Threshold Population Inversion and Stimulated Emission Cross-Section 146
8.5 Paramagnetic Ion Solid-State Lasers 147
8.6 The Nd:YAG Laser 147
8 6.1 Efiective Spontaneous Emission Coefficient 152
8.6.2 Example-Threshold Pump Energy of a Pulsed Nd:YAG Laser 153
8.7 CW Operation of the Nd:YAG Laser 154
8.8 TheNd3+ Glass Laser 154
8.9 Geometrical Arrangements for Optical Pumping 159
8.9.1 Axisymmetric Optical Pumping of a Cylindrical Rod 159
8.10 High Power Pulsed Solid-State Lasers 166
8.11 Diode-Pumped Solid-State Lasers 167
8.12 Relaxation Oscillations(Spiking) 168
8.13 Rate Equations for Relaxation Oscillation 170
8.14 Undamped Relaxation Oscillations 174
8.15 Giant Pulse(Q-Switched)Lasers 175
8.16 Theoretical Description of the Q-Switching Process 179
8.16.1 Example Calculation of Q-Switched Pulse Characteristics 182
8.17 Problems 183
References 183
9 Gas Lasers 185
9.1 Introduction 185
9.2 Optical Pumping 185
9.3 Electron lmpact Excitation 187
9.4 The Argon Ion Laser 188
9.5 Pumping Saturation in Gas Laser Systems 190
9.6 Pulsed Ion Lasers 191
9.7 CW Ion Lasers 192
9.8 'Metal'Vapor Ion Lasers 196
9.9 Gas Discharges for Exciting Gas Lasers 199
9.10 Rate Equations for Gas Discharge Lasers 201
9.11 Problems 204
References 205
10 Molecular Gas Lasers Ⅰ 207
10.1 Introduction 207
10.2 The Energy Levels of Molecules 207
10.3 Vibrations of a Polyatomic Molecule 212
10.4 Rotational Energy States 214
10.5 Rotational Populations 214
10.6 The Overall Energy State of a Molecule 216
10.7 The Carbon Dioxide Laser 217
10.8 The Carbon Monoxide Laser 222
10.9 Other Gas Discharge Molecular Lasers 224
References 224
11 Molecular Gas Lasers Ⅱ 225
11.1 Introduction 225
11.2 Gas Transport Lasers 225
11.3 Gas Dynamic Lasers 228
11.4 High Pressure Pulsed Gas Lasers 232
11.5 Ultraviolet Molecular Gas Lasers 238
11.6 Photodissociation Lasers 241
11.7 Chemieal Lasers 241
11.8 Far-Infrared Lasers 244
11.9 Problems 244
References 246
12 Tunable Lasers 248
12.1 Introduction 248
12.2 Organic Dye Lasers 248
12.2.1 Energy Level Structure 248
12.2.2 Pulsed Laser Excitation 251
12.2.3 CW Dye Laser Operation 252
12.3 Calculation of Threshold Pump Power in Dye Lasers 253
12.3.1 Pulsed Operation 256
12.3.2 CW Operation 259
12.4 Inorganic Liquid Lasers 260
12.5 Free Electron Lasers 260
12.6 Problems 266
References 266
13 Semiconductor Lasers 267
13.1 Introduction 267
13.2 Semiconductor Physics Background 267
13.3 Carrier Concentrations 271
13.4 Intrinsic and Extrinsic Semiconductors 274
13.5 The p-n Junction 275
13.6 Recombination and Luminescence 280
13.6.1 The Spectrum of Recombination Radiation 281
13.6.2 External Quantum Efficiency 283
13.7 Heterojunctions 285
13.7.1 Ternary and Quaternary Lattice-Matched Materials 285
13.7 2 Energy Barriers and Rectification 286
13.7.3 The Double Heterostructure 286
13.8 Semiconductor Lasers 290
13.9 The Gain Coefficient of a Semiconductor Laser 292
13.9.1 Estimation of Semiconductor Laser Gain 293
13.10 Threshold Current and Powet-Voltage Characteristics 295
13.11 Longitudinal and Transverse Modes 296
13.12 Semiconductor Laser Structures 297
13.12.1 Distributed Feedback(DFB)and Distributed Bragg Reflection(DBR) Lasers 299
13.13 Surface Emitting Lasers 304
13.14 Laser Diode Arrays and Broad Area Lasers 306
13.15 Quantum Well Lasers 307
13.16 Problems 310
References 311
14 Analysis of Optical Systems Ⅰ 312
14.1 Introduction 312
14.2 The Propagation of Rays and Waves through Isotropic Media 312
14.3 Simple Reflection and Refraction Analysis 313
14.4 Paraxial Ray Analysis 316
14.4.1 Matrix Formulation 316
14.4.2 Ray Tracing 324
14.4.3 Imaging and Magnification 325
14.5 The Use of Impedances in Optics 327
14.5.1 Reflectance for Waves Incident on an Interface at Oblique Angles 331
14.5.2 Brewster's Angle 332
14.5.3 Transformation of Impedance through Multilayer Optical Systems 332
14.5.4 Polarization Changes 334
14.6 Problems 335
References 336
15 Analysis of Optical Systems Ⅱ 337
15.1 Introduction 337
15.2 Periodic Optical Systems 337
15.3 The Identical Thin Lens Waveguide 339
15.4 The Propagation of Rays in Mirror Resonators 340
15.5 The Propagation of Rays in Isotropic Media 342
15.6 The Propagation of Spherical Waves 346
15.7 Problems 347
References 347
16 Optics ofGaussian Beams 348
16.1 Introduction 348
16.2 Beam-Like Solutions of the Wave Equation 348
16.3 Higher Order Modes 354
16.3.1 Beam Modes with Cartesian Symmetry 354
16.3.2 Cylindrically Symmetric Higher Order Beams 355
16.4 The Transformation of a Gaussian Beam by a Lens 357
16.5 Transformation of Gaussian Beams bv General Optical Systems 371
16.6 Gaussian Beams in Lens Waveguides 371
16.7 The Propagation of a Gaussian Beam in a Medium with a Quadratic Refractive Index Profile 372
16.8 The Propagation of Gaussian Beams in Media with Spatial Gain or Absorption Variations 372
16.9 Propagation in a Medium with a Parabolic Gain Profile 373
16.10 Gaussian Beams in Plane and Spherical Mirror Resonators 375
16.11 Symmetrical Resonators 377
16.12 An Example of Resonator Design 379
16.13 Difiraction Losses 381
16.14 Unstable Resonators 382
16.15 Problems 384
References 386
17 Optical Fibers and Waveguides 387
17.1 Introduction 387
17.2 Ray Theory of Cylindrical Optical Fibers 387
17.2.1 Meridional Rays in a Step-Index Fiber 387
17.2.2 Step-lndex Fibers 390
17.2.3 Graded-Index Fibers 392
17.2.4 Bound,Refracting,and Tunnelling Rays 393
17.3 Ray Theory of a Dielectric Slab Guide 395
17.4 The Goos-H？inchen Shift 397
17.5 Wave Theory of the Dielectric Slab Guide 399
17.6 P-Waves in the Slab Guide 400
17.7 Dispersion Curves and Field Distributions in a Slab Waveguide 404
17.8 S-Waves in the Slab Guide 406
17.9 Practical Slab Guide Geometries 407
17.10 Cylindrical Dielectric Waveguides 408
17.10.1 Fields in the Core 413
17.10.2 Fields in the Cladding 414
17.10.3 Boundary Conditions 414
17.11 Modes and Field Patterns 415
17.12 The Weakly-Guiding Approximation 416
17.13 Mode Patterns 417
17.14 Cutoff Frequencies 419
17.14.1 Example 421
17.15 Multimode Fibers 423
17.16 Fabrication ofOptical Fibers 423
17.17 Dispersion in Optical Fibers 425
17.17.1 Material Dispersion 427
17.17.2 Waveguide Dispersion 428
17.18 Solitons 430
17.19 Erbium-Doped Fiber Amplifiers 430
17.20 Coupling Optical Sources and Detectors to Fibers 433
17.20.1 Fiber Connectors 434
17.21 Problems 435
References 437
18 Optics of Anisotropic Media 438
18.1 Introduction 438
18.2 The Dielectric Teusor 438
18.3 Stored Electromagnetic Energy in Anisotropic Media 440
18.4 Propagation of Monochromatic Plane Waves in Anisotropic Media 441
18.5 The Two Possible Directions of D for a Given Wave Vector are Orthogonal 443
18.6 Angular Relationships between D,E,H,k,and the Poynting Vector S 444
18.7 The Indicatrix 446
18.8 Uniaxial Crystals 448
18.9 Index Surfaces 450
18.10 Other Surfaces Related to the Uniaxial Indicatrix 452
18.11 Huygenian Constructions 453
18.12 Retardation 457
18.13 Biaxial Crystals 461
18.14 Intensity Transmission Through Polarizer/Waveplate/Polarizer Combin-ations 464
18.14.1 Examples 465
18.15 The Jones Calculus 465
18.15.1 The Jones Vector 466
18.15.2 The Jones Matrix 467
18.16 Problems 470
References 471
19 The Electro-Optic and Acousto-Optic Effects and Modulation of Light Beams 472
19.1 Introduction to the Electro-Optic Effect 472
19.2 The Linear Electro-Optic Effect 472
19.3 The Quadratic Electro-Optic Effect 479
19.4 Longitudinal Electro-Optic Modulation 480
19.5 Transverse Electro-optic Modulation 482
19.6 Electro-Optic Amplitude Modulation 486
19.7 Electro-Optic Phase Modulation 488
19.8 High Frequency Waveguide Electro-Optic Modulators 489
19.8.1 Straight Electrode Modulator 490
19.9 Other High Frequency Electro-Optic Devices 493
19.10 Electro-Optic Beam Deflectors 495
19.11 Acousto-Optic Modulators 495
19.12 Applications of Acousto-Optic Modulators 502
19.12.1 Diffraction Efficiency of TeO2 502
19.12.2 Acousto-Optic Modulators 502
19.12.3 Acousto-Optic Beam Deflectors and Scanners 503
19.12.4 RF Spectrum Analysis 504
19.13 Construction and Materials for Acousto-Optic Modulators 504
19.14 Problems 507
References 507
20 Introduction to Nonlinear Processes 508
20.1 Introduction 508
20.2 Anharmonic Potentials and Nonlinear Polarization 508
20.3 Nonlinear Susceplibilities and Mixing Coefficients 512
20.4 Second Harmonic Generation 514
20.4.1 Symmetries and Kleinman's Conjecture 516
20.5 The Linear Electro-Optic Effect 516
20.6 Parametric and Other Nonlinear Processes 517
20 7 Macroscopic and Microscopic Susceptibilities 518
20.8 Problems 522
References 522
21 Wave Propagation in Nonlinear Media 524
21.1 Introduction 524
21.2 Electromagnetic Wayes and Nonlinear Polarization 524
21.3 Second Harmonic Generation 528
21.4 The Effective Nonlinear Coefficient deff 530
21.5 Phase Matching 532
21.5.1 Second Harmonic Generation 533
21.5.2 Example 533
21.5.3 Phase Matching in Sum-Frequency Generation 535
21.6 Beam Walk-Off and 90°Phase Matching 535
21.7 Second Harmonic Generation with Gaussian Beams 536
21.7.1 Intracavity SHG 537
21.7.2 External SHG 538
21.7.3 The Effects of Depletion on Second Harmonic Generation 538
21.8 Up-Conversion and Difference-Frequency Generation 541
21.9 Optical Parametric Amplification 542
21.9.1 Example 544
21.10 Parametric Oscillators 545
21.10.1 Example 547
21.11 Parametric Oscillator Tuning 548
21.12 Phase Conjugation 550
21.12.1 Phase Conjugation in CS2 553
21.13 Optical Bistability 554
21.14 Practical Details of the Use of Crystals for Nonlinear Applications 557
21.15 Problems 558
References 559
22 Detection of Optical Radiation 561
22.1 Introduction 561
22.2 Noise 561
22.2.1 Shot Noise 561
22.2.2 Johnson Noise 564
22 2.3 Generation-Recombination Noise and l/fNoise 567
22.3 Detector Performance Parameters 568
22.3.1 Noise Equivalent Power 568
22.3.2 Detectivity 569
22 3.3 Frequency Response and Time Constant 569
22.4 Practical Characteristics of Optical Derectors 570
22.4 1 Photoemissive Detectors 570
22.4.2 Photoconductive Detectors 576
22.4.3 Photovoltaic Detectors（Photodiodes） 582
22.4.4 p-i-n Photodiodes 586
22.4.5 Avalanche Photodiodes 587
22.5 Thermal Delectors 589
22.6 Detection Limits for Optical Detector Systems 591
22.6.1 Noise in Photomultipliers 592
22.6.2 Photon Counting 593
22.6.3 Signal-to-Noise Ratio in Direct Detection 594
22.6.4 Direct Detection with p-i-n Photodiodes 595
22.6.5 Direct Detection with APDs 597
22.7 Coherent Detection 598
22.8 Bit-Error Rate 603
References 605
23 Coherence Theory 607
23.1 Introduction 607
23.2 Square-Law Detectors 607
23.3 The Analytic Signal 608
23.3.1 Hilbert Transforms 610
23.4 Correlation Functions 611
23.5 Temporal and Spatial Coherence 614
23.6 Spatial Coherence 618
23.7 Spatial Coherence with an Extended Source 620
23.8 Propagation Laws of Partial Coherence 622
23.9 Propagation from a Finite Plane Surface 625
23.10 van Cittert-Zernike Theorem 630
23.11 Spatial Coherence of a Quasi-MonochromaticfUniform,Spatially Incoherent Circular Source 632
23.12 Intensity Correlation Interferometry 634
23.13 Intensity Fluctuations 635
23.14 Photon Statistics 638
23.14.1 Constant Intensity Source 639
23.14.2 Random Intensities 640
23.15 The Hanbury-Brown-Twiss Interferometer 643
23.16 Hanbury-Brown-Twiss Experiment with Photon Count Correlations 645
References 646
24 Laser Applications 647
24.1 Optical Communication Systems 647
24.1.1 Introduction 647
24.1.2 Absorption in Optical Fibers 649
24.1.3 Optical Conmmunication Networks 650
24.1.4 Optical Fiber Network Architectures 651
24.1.5 Coding Schemes in Optical Networks 653
24.1.6 Line-of-Sight Optical Links 654
24.2 Holography 656
24 2.1 Wavefront Reconstruction 656
24.2.2 The Hologram as a Diffraction Grating 660
24.2.3 Volume Holograms 661
24.3 Laser Isotope Separation 664
24.4 Laser Plasma Generation and Fusion 669
24.5 Medical Applications of Lasers 671
24.5.1 Laser Angioplasty 673
References 673
Appendix 1 Optical Terminology 676
Appendix 2 Theδ-Function 679
Appendix 3 Black-Body Radiation Formulas 681
Appendix 4 RLC Cireuit 683
A4.1 Analysis of a Driven RLC Circuit 683
Appendix 5 Storage and Transport of Energy by Electromagnetic Fields 686
Appendix 6 The Reflection and Refraction of a Plane Electromagnetic Wave at the Boundary Between Two Isotropic Media of Different Refractive Index 689
Appendix 7 The Vector Differential Equation for Light Rays 692
Appendix 8 Symmetry Properties of Crystals and the 32 Crystal Classes 695
A8.1 Class 6mm 696
A8.2 Class 42m 696
A8.3 Class 222 697
Appendix 9 Tensors 698
Appendix 10 Bessel Function Relations 701
Appendix 11 Green's Functions 702
Appendix 12 Recommended Values of Some Physical Constants 705
Index 706