Principles of Lasers

1441913017......Page 1
Principles of Lasers, 5th Edition......Page 2
Preface......Page 6
Contents......Page 9
List of Examples......Page 17
1.1 Spontaneous and Stimulated Emission, Absorption......Page 20
1.2 The Laser Idea......Page 23
1.3 Pumping Schemes......Page 25
1.4 Properties of Laser Beams......Page 27
1.4.2 Coherence......Page 28
1.4.3 Directionality......Page 29
1.4.4 Brightness......Page 30
1.4.5 Short Time Duration......Page 32
1.6 Organization of the Book......Page 33
 Problems......Page 34
2.2 Summary of Blackbody Radiation Theory......Page 35
2.2.1 Modes of a Rectangular Cavity......Page 37
2.2.2 The Rayleigh-Jeans and Planck Radiation Formula......Page 40
2.2.3 Planck's Hypothesis and Field Quantization......Page 42
2.3.1 Semiclassical Approach......Page 44
2.3.2 Quantum Electrodynamics Approach......Page 48
2.3.3 Allowed and Forbidden Transitions......Page 49
2.4.1 Rates of Absorption and Stimulated Emission......Page 50
2.4.2 Allowed and Forbidden Transitions......Page 54
2.4.3 Transition Cross Section, Absorption and Gain Coefficient......Page 55
2.4.4 Einstein Thermodynamic Treatment......Page 59
2.5.1 Homogeneous Broadening......Page 61
2.5.2 Inhomogeneous Broadening......Page 65
2.5.3 Concluding Remarks......Page 67
2.6.1 Mechanisms of Nonradiative Decay......Page 68
2.6.2 Combined Effects of Radiative and Nonradiative Processes......Page 74
2.7.1 Degenerate Levels......Page 76
2.7.2 Strongly Coupled Levels......Page 78
2.8.1 Saturation of Absorption: Homogeneous Line......Page 82
2.8.2 Gain Saturation: Homogeneous Line......Page 85
2.8.3 Inhomogeneously Broadened Line......Page 87
2.9 Decay of an Optically Dense Medium......Page 88
2.9.2 Amplified Spontaneous Emission......Page 89
2.10 Concluding Remarks......Page 94
 Problems......Page 95
 References......Page 96
3.1.1 Energy Levels......Page 98
3.1.2 Level Occupation at Thermal Equilibrium......Page 102
3.1.3 Stimulated Transitions......Page 104
3.1.4 Radiative and Nonradiative Decay......Page 108
3.2.1 Electronic States......Page 110
3.2.2 Density of States......Page 114
3.2.3 Level Occupation at Thermal Equilibrium......Page 115
3.2.4 Stimulated Transitions......Page 118
3.2.5 Absorption and Gain Coefficients......Page 121
3.2.6 Spontaneous Emission and Nonradiative Decay......Page 127
3.2.7 Concluding Remarks......Page 129
3.3.1 Electronic States......Page 130
3.3.2 Density of States......Page 133
3.3.3 Level Occupation at Thermal Equilibrium......Page 135
3.3.4 Stimulated Transitions......Page 136
3.3.5 Absorption and Gain Coefficients......Page 138
3.3.6 Strained Quantum Wells......Page 142
3.4 Quantum Wires and Quantum Dots......Page 143
 Problems......Page 145
 References......Page 146
4.2 Matrix Formulation of Geometrical Optics......Page 148
4.3 Wave Reflection and Transmission at a Dielectric Interface......Page 154
4.4 Multilayer Dielectric Coatings......Page 156
4.5.1 Properties of a Fabry-Perot Interferometer......Page 159
4.5.2 The Fabry-Perot Interferometer as a Spectrometer......Page 163
4.6 Diffraction Optics in the Paraxial Approximation......Page 164
4.7.1 Lowest-Order Mode......Page 167
4.7.2 Free Space Propagation......Page 170
4.7.3 Gaussian Beams and the ABCD Law......Page 173
4.7.4 Higher-Order Modes......Page 175
 Problems......Page 176
 References......Page 178
5.1 Introduction......Page 179
5.2 Eigenmodes and Eigenvalues......Page 183
5.3 Photon Lifetime and Cavity Q......Page 185
5.4 Stability Condition......Page 187
5.5.1 Resonators with Infinite Aperture......Page 191
5.5.1.1 Eigenmodes......Page 192
5.5.1.2 Eigenvalues......Page 196
5.5.1.3 Standing- and Traveling-Waves in a Two-Mirror Resonator......Page 198
5.5.2 Effects of a Finite Aperture......Page 199
5.5.3 Dynamically and Mechanically Stable Resonators......Page 202
5.6 Unstable Resonators......Page 205
5.6.1 Geometrical-Optics Description......Page 206
5.6.2 Wave-Optics Description......Page 208
5.6.4 Variable-Reflectivity Unstable Resonators......Page 212
 Problems......Page 216
 References......Page 219
6.1 Introduction......Page 220
6.2.1 Pumping Systems......Page 223
6.2.2 Absorption of Pump Light......Page 226
6.2.3 Pump Efficiency and Pump Rate......Page 228
6.3 Laser Pumping......Page 230
6.3.1 Laser Diode Pumps......Page 232
6.3.2.1 Longitudinal Pumping......Page 234
6.3.2.2 Transverse Pumping......Page 239
6.3.3 Pump Rate and Pump Efficiency......Page 240
6.3.4 Threshold Pump Power for Four-Level and Quasi-Three-Level Lasers......Page 243
6.3.5 Comparison Between Diode-pumping and Lamp-pumping......Page 245
6.4 Electrical Pumping......Page 247
6.4.1 Electron Impact Excitation......Page 251
6.4.1.1 Electron Impact Cross Section......Page 252
6.4.2 Thermal and Drift Velocities......Page 255
6.4.3 Electron Energy Distribution......Page 257
6.4.4 The Ionization Balance Equation......Page 260
6.4.5 Scaling Laws for Electrical Discharge Lasers......Page 262
6.4.6 Pump Rate and Pump Efficiency......Page 263
 Problems......Page 265
 References......Page 268
7.2 Rate Equations......Page 269
7.2.1 Four-Level Laser......Page 270
7.2.2 Quasi-Three-Level Laser......Page 275
7.3 Threshold Conditions and Output Power: Four-Level Laser......Page 277
7.3.1 Space-Independent Model......Page 278
7.3.2 Space-Dependent Model......Page 284
7.4.1 Space-Independent Model......Page 293
7.4.2 Space-Dependent Model......Page 294
7.5 Optimum Output Coupling......Page 297
7.6 Laser Tuning......Page 299
7.7 Reasons for Multimode Oscillation......Page 301
7.8.1 Single-Transverse-Mode Selection......Page 304
7.8.2 Single-Longitudinal-Mode Selection......Page 305
7.8.2.1 Fabry-Perot Etalons as Mode-Selective Elements......Page 306
7.8.2.2 Single Mode Selection via Unidirectional Ring Resonators......Page 308
7.9 Frequency-Pulling and Limit to Monochromaticity......Page 311
7.10 Laser Frequency Fluctuations and Frequency Stabilization......Page 314
7.11 Intensity Noise and Intensity Noise Reduction......Page 318
7.12 Conclusions......Page 320
 Problems......Page 322
 References......Page 324
8.2 Relaxation Oscillations......Page 326
8.2.1 Linearized Analysis......Page 328
8.3 Dynamical Instabilities and Pulsations in Lasers......Page 331
8.4.1 Dynamics of the Q-Switching Process......Page 332
8.4.2 Methods of Q-Switching......Page 334
8.4.2.1 Electro-Optical Q-Switching......Page 335
8.4.2.2 Rotating Prisms......Page 336
8.4.2.3 Acousto-Optic Q-Switches......Page 337
8.4.2.4 Saturable-Absorber Q-Switch......Page 338
8.4.3 Operating Regimes......Page 341
8.4.4 Theory of Active Q-Switching......Page 342
8.5 Gain Switching......Page 350
8.6 Mode-Locking......Page 352
8.6.1 Frequency-Domain Description......Page 353
8.6.2 Time-Domain Picture......Page 357
8.6.3.1 Active Mode-Locking......Page 359
8.6.3.2 Passive Mode Locking......Page 363
8.6.4.1 Phase-Velocity, Group-Velocity and Group-Delay-Dispersion......Page 369
8.6.4.2 Limitation on Pulse Duration due to Group-Delay Dispersion......Page 371
8.6.4.3 Dispersion Compensation......Page 373
8.6.4.4 Soliton-type of Mode-Locking......Page 374
8.6.5 Mode-Locking Regimes and Mode-Locking Systems......Page 377
8.7 Cavity Dumping......Page 381
8.8 Concluding Remarks......Page 382
 Problems......Page 383
 References......Page 385
9.2 Solid-State Lasers......Page 387
9.2.1 The Ruby Laser......Page 389
9.2.2.1 Nd:YAG......Page 392
9.2.2.2 Nd:Glass......Page 395
9.2.3 Yb:YAG......Page 396
9.2.4 Er:YAG and Yb:Er:glass......Page 398
9.2.5 Tm:Ho:YAG......Page 399
9.2.6 Fiber Lasers......Page 401
9.2.7 Alexandrite Laser......Page 403
9.2.8 Titanium Sapphire Laser......Page 406
9.2.9 Cr:LISAF and Cr:LICAF......Page 408
9.3.1 Photophysical Properties of Organic Dyes......Page 409
9.3.2 Characteristics of Dye Lasers......Page 413
9.4.1 Principle of Semiconductor Laser Operation......Page 417
9.4.2 The Homojunction Laser......Page 419
9.4.3 The Double-Heterostructure Laser......Page 420
9.4.4 Quantum Well Lasers......Page 425
9.4.5 Laser Devices and Performances......Page 428
9.4.6 Distributed Feedback and Distributed Bragg Reflector Lasers......Page 431
9.4.7 Vertical Cavity Surface Emitting Lasers......Page 435
9.4.8 Applications of Semiconductor Lasers......Page 437
 Problems......Page 439
 References......Page 441
10.2 Gas Lasers......Page 443
10.2.1.1 Helium-Neon Lasers......Page 444
10.2.1.2 Copper Vapor Lasers......Page 449
10.2.2.1 Argon Laser......Page 451
10.2.2.2 He-Cd Laser......Page 454
10.2.3.1 The CO2 Laser......Page 456
10.2.3.2 The CO Laser......Page 466
10.2.3.3 The N2 Laser......Page 468
10.2.3.4 Excimer Lasers......Page 469
10.3.1 The HF Laser......Page 473
10.4 The Free-Electron Laser......Page 477
10.5 X-ray Lasers......Page 481
 Problems......Page 483
 References......Page 485
11.2 Monochromaticity......Page 487
11.3 First-Order Coherence......Page 488
11.3.1 Degree of Spatial and Temporal Coherence......Page 489
11.3.2 Measurement of Spatial and Temporal Coherence......Page 492
11.3.3 Relation Between Temporal Coherence and Monochromaticity......Page 495
11.3.5 Spatial and Temporal Coherence of Single-Mode and Multimode Lasers......Page 497
11.3.6 Spatial and Temporal Coherence of a Thermal Light Source......Page 500
11.4.1 Beams with Perfect Spatial Coherence......Page 501
11.4.2 Beams with Partial Spatial Coherence......Page 503
11.4.3 The M2 Factor and the Spot-Size Parameter of a Multimode Laser Beam......Page 504
11.5 Laser Speckle......Page 507
11.6 Brightness......Page 510
11.7 Statistical Properties of Laser Light and Thermal Light......Page 511
11.8 Comparison Between Laser Light and Thermal Light......Page 513
 Problems......Page 515
 References......Page 516
12.1 Introduction......Page 517
12.2 Spatial Transformation: Propagation of a Multimode Laser Beam......Page 518
12.3 Amplitude Transformation: Laser Amplification......Page 519
12.3.1 Examples of Laser Amplifiers: Chirped-Pulse-Amplification......Page 524
12.4.1 Physical Picture......Page 528
12.4.1.1 Second-Harmonic Generation......Page 529
12.4.1.2 Parametric Oscillation......Page 536
12.4.2 Analytical Treatment......Page 538
12.4.2.1 Parametric Oscillation......Page 540
12.4.2.2 Second-Harmonic Generation......Page 544
12.5 Transformation in Time: Pulse Compression and Pulse Expansion......Page 547
12.5.1 Pulse Compression......Page 548
12.5.2 Pulse Expansion......Page 553
 Problems......Page 555
 References......Page 556
A Semiclassical Treatment of the Interaction of Radiation with Matter......Page 558
B Lineshape Calculation for Collision Broadening......Page 564
C Simplified Treatment of Amplified Spontaneous Emission......Page 567
 References......Page 570
D Calculation of the Radiative Transition Rates of Molecular Transitions......Page 571
E.1 Four-Level Laser......Page 574
E.2 Quasi-Three-Level Laser......Page 580
F.1 Active Mode-Locking......Page 583
F.2 Passive Mode-Locking......Page 588
 References......Page 589
G Propagation of a Laser Pulse Through a Dispersive Medium or a Gain Medium......Page 590
 References......Page 594
H Higher-Order Coherence......Page 595
I Physical Constants and Useful Conversion Factors......Page 598
Chapter 2......Page 600
Chapter 3......Page 602
Chapter 4......Page 603
Chapter 5......Page 604
Chapter 6......Page 605
Chapter 7......Page 606
Chapter 8......Page 608
Chapter 10......Page 609
Chapter 11......Page 610
Chapter 12......Page 611
 Index......Page 612