Acknowledgments xi -- Preface xiii -- Foreword xvii -- List of Contributors xix -- 1 General Introduction 1 /Hans Hartnagel, Antti V. Raisanen, and Magdalena Salazar-Palma -- 2 Principles of THz Generation 3 /Sascha Preu, Gottfried H. DŠohler, Stefan Malzer, Andreas StŠohr, Vitaly Rymanov, Thorsten GŠobel, Elliott R. Brown, Michael Feiginov, Ramón Gonzalo, Miguel Beruete, and Miguel Navarro-Cya -- 2.1 Overview 3 -- 2.2 THz Generation by Photomixers and Photoconductors 5 -- 2.2.1 Principle of Operation 5 -- 2.2.2 Basic Concepts and Design Rules 7 -- 2.2.3 Thermal Constraints 21 -- 2.2.4 Electrical Constraints 23 -- 2.2.5 Device Layouts of Photoconductive Devices 35 -- 2.2.6 Device Layouts of p-i-n Diode-Based Emitters 47 -- 2.3 Principles of Electronic THz Generation 53 -- 2.3.1 Oscillators with Negative Differential Conductance 54 -- 2.3.2 Multipliers (Schottky Diodes, Hetero-Barrier Varactors) 56 -- 2.3.3 Plasmonic Sources 58 -- References 61 -- 3 Principles of Emission of THzWaves 69 /Luis Enrique Garcya Munoz, Sascha Preu, Stefan Malzer, Gottfried H. DŠohler, Javier Montero-de-Paz, Ramón Gonzalo, David González-Ovejero, Daniel Segovia-Vargas, Dmitri Lioubtchenko, and Antti V. Raisanen -- 3.1 Fundamental Parameters of Antennas 69 -- 3.1.1 Radiation Pattern 69 -- 3.1.2 Directivity 71 -- 3.1.3 Gain and Radiation Efficiency 71 -- 3.1.4 Effective Aperture Area and Aperture Efficiency 72 -- 3.1.5 Phase Pattern and Phase Center 72 -- 3.1.6 Polarization 72 -- 3.1.7 Input Impedance and Radiation Resistance 72 -- 3.1.8 Bandwidth 73 -- 3.2 Outcoupling Issues of THz Waves 73 -- 3.2.1 Radiation Pattern of a Dipole over a Semi-Infinite Substrate 75 -- 3.2.2 Radiation Pattern of a Dipole in a Multilayered Medium 79 -- 3.2.3 Anomalies in the Radiation Pattern 82 -- 3.3 THz Antenna Topologies 84 -- 3.3.1 Resonant Antennas 85 -- 3.3.2 Self-Complementary Antennas 87 -- 3.4 Lenses 90 -- 3.4.1 Lens Design 90 -- 3.5 Techniques for Improving the Performance of THz Antennas 93 -- 3.5.1 Conjugate Matching Technique 93.

3.5.2 Tapered Slot Antenna on Electromagnetic Band Gap Structures 99 -- 3.6 Arrays 107 -- 3.6.1 General Overview and Spectral Features of Arrays 107 -- 3.6.2 Large Area Emitters 113 -- References 157 -- 4 Propagation at THz Frequencies 160 /Antti V. Raisanen, Dmitri Lioubtchenko, Andrey Generalov, J. Anthony Murphy, Créidhe O'Sullivan, Marcin L. Gradziel, Neil Trappe, Luis Enrique Garcia Munoz, Alejandro Garcia-Lamperez, and Javier Montero-de-Paz -- 4.1 Helmholtz Equation and Electromagnetic Modes of Propagation 160 -- 4.2 THz Waveguides 167 -- 4.2.1 Waveguides with a Single Conductor: TE and TM Modes 168 -- 4.2.2 Waveguides with Two or More Conductors: TEM and Quasi-TEM Modes 173 -- 4.2.3 Waveguides with No Conductor: Hybrid Modes 177 -- 4.3 Beam Waveguides 183 -- 4.3.1 Gaussian Beam 183 -- 4.3.2 Launching and Focusing Components: Horns, Lenses, and Mirrors 187 -- 4.3.3 Other Components Needed in Beam Waveguides 193 -- 4.3.4 Absorbers 195 -- 4.3.5 Modeling Horns Using Mode Matching 195 -- 4.3.6 Multimode Systems and Partially Coherent Propagation 199 -- 4.3.7 Modeling Techniques for THz Propagation in THz Systems 201 -- 4.4 High Frequency Electric Characterization of Materials 202 -- 4.4.1 Drude Model 203 -- 4.4.2 Lorentz-Drude Model 204 -- 4.4.3 Brendel-Bormann Model 205 -- 4.5 Propagation in Free Space 205 -- 4.5.1 Link Budget 205 -- 4.5.2 Atmospheric Attenuation 206 -- References 207 -- 5 Principles of THz Direct Detection 212 /Elliott R. Brown, and Daniel Segovia-Vargas -- 5.1 Detection Mechanisms 212 -- 5.1.1 E-Field Rectification 213 -- 5.1.2 Thermal Detection 215 -- 5.1.3 Plasma-Wave, HEMT, and MOS-Based Detection 220 -- 5.2 Noise Mechanisms 223 -- 5.2.1 Noise from Electronic Devices 223 -- 5.2.2 Phonon Noise 225 -- 5.2.3 Photon Noise with Direct Detection 227 -- 5.3 THz Coupling 230 -- 5.3.1 THz Impedance Matching 230 -- 5.3.2 Planar-Antenna Coupling 231 -- 5.3.3 Exemplary THz Coupling Structures 232 -- 5.3.4 Output-Circuit Coupling 235 -- 5.4 External Responsivity Examples 235.

5.4.1 Rectifiers 235 -- 5.4.2 Micro-Bolometers 236 -- 5.5 System Metrics 239 -- 5.5.1 Signal-to-Noise Ratio 239 -- 5.5.2 Sensitivity Metrics 240 -- 5.6 Effect of Amplifier Noise 243 -- 5.7 A Survey of Experimental THz Detector Performance 244 -- 5.7.1 Rectifiers 246 -- 5.7.2 Thermal Detectors 247 -- 5.7.3 CMOS-Based and Plasma-Wave Detectors 249 -- References 250 -- 6 THz Electronics 254 /Michael Feiginov, Ramƒon Gonzalo, Itziar Maestrojuán, Oleg Cojocari, Matthias Hoefle, and Ernesto Limiti -- 6.1 Resonant-Tunneling Diodes 254 -- 6.1.1 Historic Introduction 254 -- 6.1.2 Operating Principles of RTDs 255 -- 6.1.3 Charge-Relaxation Processes in RTDs 256 -- 6.1.4 High-Frequency RTD Conductance 259 -- 6.1.5 Operating Principles of RTD Oscillators 260 -- 6.1.6 Limitations of RTD Oscillators 261 -- 6.1.7 Overview of the State of the Art Results 264 -- 6.1.8 RTD Oscillators versus Other Types of THz Sources 265 -- 6.1.9 Future Perspectives 265 -- 6.2 Schottky Diode Mixers: Fundamental and Harmonic Approaches 265 -- 6.2.1 Sub-Harmonic Mixers 267 -- 6.2.2 Circuit Fabrication Technologies 270 -- 6.2.3 Characterization Technologies 272 -- 6.2.4 Advanced Configuration Approach 276 -- 6.2.5 Imaging Applications of Schottky Mixers 277 -- 6.3 Solid-State THz Low Noise Amplifiers 278 -- 6.3.1 Solid-State Active Devices and Technologies for Low Noise Amplification 280 -- 6.3.2 Circuit and Propagation Issues for TMIC 282 -- 6.3.3 Low Noise Amplifier Design and Realizations 284 -- 6.3.4 Perspectives 287 -- 6.4 Square-Law Detectors 288 -- 6.4.1 Characterization and Modeling of Low-Barrier Schottky Diodes 289 -- 6.4.2 Design of Millimeter-Wave Square-Law Detectors 291 -- 6.5 Fabrication Technologies 292 -- 6.5.1 Overview of Fabrication Approaches of Schottky Structures for Millimeter-Wave Applications 293 -- 6.5.2 Film-Diode Process 296 -- References 299 -- 7 Selected Photonic THz Technologies 304 /Cyril C. Renaud, Andreas StŠohr, Thorsten Goebel, Frédéric Van Dijk, and Guillermo Carpintero.

7.1 Photonic Techniques for THz Emission and Detection 304 -- 7.1.1 Overall Photonic System 304 -- 7.1.2 Basic Components Description 306 -- 7.1.3 Systems Parameters, Pulsed versus CW 307 -- 7.2 Laser Sources for THz Generation 309 -- 7.2.1 Pulsed Laser Sources 309 -- 7.2.2 Continous Wave (CW) Sources 312 -- 7.2.3 Noise Reduction Techniques 314 -- 7.2.4 Photonic Integrated Laser Sources 315 -- 7.3 Photodiode for THz Emission 320 -- 7.3.1 PD Limitations and Key Parameters 320 -- 7.3.2 Traveling Wave UTC-PD Solution 322 -- 7.4 Photonically Enabled THz Detection 324 -- 7.4.1 Pulsed Terahertz Systems 325 -- 7.4.2 Optically Pumped Mixers 328 -- 7.5 Photonic Integration for THz Systems 331 -- 7.5.1 Hybrid or Monolithic Integrations 332 -- 7.5.2 Monolithic Integration of Subsystems 333 -- 7.5.3 Foundry Model for Integrated Systems 334 -- References 335 -- 8 Selected Emerging THz Technologies 340 /Christian Damm, Harald G. L. Schwefel, Florian Sedlmeir, Hans Hartnagel, Sascha Preu, and Christian Weickhmann -- 8.1 THz Resonators 340 -- 8.1.1 Principles of Resonators 341 -- 8.1.2 Introduction to WGM Resonators 343 -- 8.1.3 Evanescent Waveguide Coupling to WGMs 345 -- 8.1.4 Resonant Scattering in WGM Resonators 346 -- 8.1.5 Nonlinear Interactions in WGM 349 -- 8.2 Liquid Crystals 350 -- 8.2.1 Introduction 350 -- 8.2.2 Characterization 357 -- 8.2.3 Applications 365 -- 8.3 Graphene for THz Frequencies 367 -- 8.3.1 Theory and Material Properties 367 -- 8.3.2 Applications 373 -- References 377 -- Index 383.