TABLE OF CONTENTS
Acknowledgments v
Preface xiii
Contributors 000
1. Coherent Sources in the Long-Wavelength Infrared Spectrum 1
Hong K. Choi
1.1 Introduction 1
1.2 Synopsis of Long-Wavelength Coherent Sources 3
1.2.1 Interband Lasers 4
1.2.2 Intersubband Quantum Cascade Lasers 8
1.2.3 Hot-Hole Lasers 10
1.2.4 Photomixing 11
1.2.5 Plasmon Emitter 12
1.3 Scope of Book 12
References 13
2. 2-?m Wavelength Lasers Employing InP-based Strained-Layer Quantum Wells 19
Manabu Mitsuhara and Mamoru Oishi
2.1 Introduction 19
2.2 Material Properties of InGaAsP 21
2.2.1 Composition Dependence of Band-Gap Energy and Lattice Constant 21
2.2.2 Miscibility Gap 22
2.3 Design Consideration of MQW Active Region 25
2.3.1 Strain and Quantum Size Effects 25
2.3.2 Critical Layer Thickness for Strained-Layer Heterostructures 31
2.3.3 Effects of Well Strain and Barrier Height on Lasing Characteristics 33
2.4 Growth and Characterization of Strained-InGaAs Quantum Wells 38
2.4.1 InGaAs/InGaAs Multiple Quantum Wells 39
2.4.2 InGaAs/InGaAsP Multiple Quantum Wells 43
2.5 Lasing Characteristics of 2-?m wavelength InGaAs-MQW Lasers 49
2.5.1 Fabry-Perot Lasers 49
2.5.2 Distributed-Feedback Lasers 53
2.6 Conclusions and Future Prospects 57
References 59
3 Antimonide Mid-IR Lasers 69
L. J. Olafsen, I. Vurgaftman, and J. R. Meyer
3.1 Introduction 69
3.2 Antimonide III-V Material System 71
3.3 Antimonide Lasers Emitting in the 2?m ? ? ? 3?m Range 74
3.3.1 Historical Development 74
3.3.2 State of the Art 76
3.4 Antimonide Lasers Emitting in the ? ? 3?m Range 82
3.4.1 Historical Development 82
3.4.2 Double-Heterostructure Lasers 82
3.4.3 Type-I Quantum-Well Lasers 88
3.4.4 Type-II Quantum-Well Lasers 95
3.4.5 Interband Cascade Lasers 103
3.5 Challenges and Issues 107
3.5.1 Antimonide Growth Immaturity 107
3.5.2 Nonradiative Recombination and Threshold 110
3.5.3 Linewidth Enhancement Factor (LEF) 115
3.5.4 Single-Mode Operation and Wavelength Tuning 118
3.5.5 Beam Quality 121
3.5.6 Thermal Management and Thermal Conductivity 123
3.6 Conclusions 125
References 126
4. Lead-Chalcogenide-based Mid-Infrared Diode Lasers 145
Uwe Peter Schieál, Joachim John, and Patrick J. McCann
4.1 Introduction 145
4.2 Homostructure Lasers 146
4.2.1 Material Properties 146
4.2.2 Device Fabrication 147
4.2.3 Device Characterization 150
4.3 Double-Heterostructure Lasers 154
4.3.1 Pb1?xEuxSeyTe1?y lasers 155
4.3.2 Pb1?xEuxSe and Pb1?xSrxSe Laser 157
4.3.3 Pb1-xSnxTe and PbSnSeTe/PbSe Lasers 167
4.3.4 Alternative Cladding Layer Materials 167
4.3.5 Quality Control Programs at Laser Components 168
4.3.6 High-Temperature Operation of Double-Heterostructure Lasers 171
4.3.7 Index-Guided Double-Heterostructure Lasers 175
4.4 Quantum-Well Lasers 177
4.5 DFB and DBR Lasers 184
4.5.1 Introduction 184
4.5.2 Experimental Work 188
4.6 IV-VI Epitaxy on BaF2 and Silicon 197
4.6.1 Introduction 197
4.6.2 Growth and Characterization of IV-VI Layers on BaF2 200
4.6.3 Growth and Characterization of IV-VI Layers on Silicon 202
4.7 Conclusion 206
References 207
5. InP and GaAs-Based Quantum Cascade Lasers 217
Jérôme Faist and Carco Sirtori
5.1 Introduction 217
5.1.1 Quantum Engineering 217
5.1.2 Organization of the Chapter 217
5.2 Quantum Cascade Laser Fundamentals 218
5.2.1 History 218
5.2.2 Unipolarity and Cascading 219
5.2.3 Intersubband Transitions 219
5.3 Fundamentals of the Three-Quantum-Well Active-Region Device 220
5.3.1 Active Region 221
5.3.2 Doping and Injection/Relaxation Region 223
5.3.3 Threshold Current Density 224
5.3.4 Effect of Cascading on the Performances of QC Lasers 226
5.4 Waveguide and Technology 227
5.4.1 Waveguide 227
5.4.2 Processing 229
5.5 High-Power, Room-Temperature Operation of Three-Quantum-Well Active Region Designs 229
5.5.1 High Power at Room Temperature 229
5.5.2 High Room-Temperature Average Power 232
5.5.3 Continuous-Wave Operation 233
5.6 GaAs-Based QC Lasers 234
5.6.1 Active Region Design 234
5.6.2 Waveguide Design 235
5.7 Role of the Conduction-Band Discontinuity 239
5.7.1 Strain-Compensated InGaAs/AlInAs Lasers for 3-5?m Operation 239
5.7.2 Role of ?Ec on the High-Temperature Performances of GaAs QC Lasers 241
5.8 Spectral Characteristics of QC Lasers 246
5.8.1 Pulsed Operation 246
5.8.2 Continuous-Wave Operation 249
5.9 Distributed Feedback Quantum Cascade Lasers 251
5.9.1 Metalized Top Grating 252
5.9.2 Index-Coupled Lasers 258
5.9.3 Lateral-Injection Surface-Grating Laser 259
5.10 Microsctructured QC Lasers 263
5.10.1 Microdisk QC Laser Resonators 264
5.10.2 High Reflectors 267
5.10.3 Buried-Heterostructure Lasers 269
5.11 Outlook on Active Region Designs and Conclusions 271
References 273
6. Widely Tunable Far-Infrared Hot-Hole Semiconductor Lasers 279
Erik Bründermann
6.1 Introduction 279
6.1.1 Tunable Germanium Lasers 281
6.1.2 Motivation 281
6.1.3 Applications 282
6.2 Hot-Hole Laser Model 283
6.2.1 Semiclassical Model 283
6.2.2 Magneto-Phonon and Magneto-Impurity Effects 288
6.2.3 Scattering Mechanisms 295
6.2.4 Optical Gain 297
6.2.5 Hall Effect and Device Geometry 301
6.2.6 Quantum Mechanical Model 306
6.2.7 Uniaxial Stress 310
6.2.8 Impurities and Self-absorption Processes 311
6.2.9 Monte Carlo Simulations 315
6.2.10 Thermal Effects 316
6.3 Laser Material Fabrication 319
6.3.1 Growth of Germanium Laser Material 319
6.3.2 Characterization 320
6.3.3 Doping by Diffusion 320
6.3.4 Ohmic Contacts for Germanium and Silicon 322
6.3.5 Laser Devices with Opposing Contacts 322
6.3.6 Laser Devices with Coplanar Contacts 323
6.3.7 Laser Devices with Multiple Contacts 323
6.4 Technology 324
6.4.1 Electric Field Generation 324
6.4.2 Magnetic Field Generation 324
6.4.3 Cooling Systems 326
6.4.4 Mode-Locking 328
6.5 Laser Emission 330
6.5.1 Germanium Laser Resonators 330
6.5.2 Spectra and Mode Structure 334
6.5.3 Output Power 336
6.6 Future Trends 337
6.6.1 Continuous-Wave Germanium Lasers 338
6.6.2 Picosecond Pulsed Germanium Lasers 339
6.6.3 Hot-Hole Silicon, Diamond, and III-V Lasers 339
6.6.4 Lasers without Magnetic Field under Uniaxial Stress 340
6.6.5 Lasers in Parallel Electric and Magnetic Fields 341
6.7 Summary 341
References 343
7. Continous THz generation with Optical Heterodyning 351
J. C. Pearson, K. A. McIntosh, and S. Verghese
7.1 Introduction 351
7.1.1 Scientific Interest in THz Waves 351
7.1.2 Source Problem 352
7.1.3 THz Generation with Photomixers 353
7.2 Requirements for Photomixing Systems 353
7.2.1 Laser Selection 354
7.2.2 Frequency and Spectral Control 356
7.2.3 THz-Wave Verification 367
7.3 Design Trade-offs for Photomixers 371
7.3.1 Basic Operation 372
7.3.2 Role of Photocarrier Lifetime 373
7.4 Antenna Design 377
7.4.1 Resonant Designs 377
7.4.2 Broadband Distributed Designs 379?
7.5 Applications 382
7.5.1 Local Oscillators 382
7.5.2 Transceiver for Spectroscopy 382
7.6 Summary 384
References 384
Index 387




Library of Congress Subject Headings for this publication: Semiconductor lasers, Far infrared lasers