Semiconductor TeraHertz Technology

GUILLERMO CARPINTERO, Universidad Carlos III de Madrid, Spain LUIS ENRIQUE GARCÍA MUÑOZ, Universidad Carlos III de Madrid, SpainHANS L. HARTNAGEL, Technische Universität Darmstadt, GermanySASCHA PREU, Technische Universität Darmstadt, GermanyANTTI V. RÄISÄNEN, Aalto University, Finland

• Acknowledgments xi Preface xiiiForeword xviiList of Contributors xix1 General Introduction 1Hans Hartnagel, Antti V. Räisänen, and Magdalena Salazar-Palma2 Principles of THz Generation 3Sascha Preu, Gottfried H. Döhler, Stefan Malzer, Andreas Stöhr, Vitaly Rymanov, Thorsten Göbel, Elliott R. Brown, Michael Feiginov, Ramón Gonzalo, Miguel Beruete, and Miguel Navarro-Cya2.1 Overview 32.2 THz Generation by Photomixers and Photoconductors 52.2.1 Principle of Operation 52.2.2 Basic Concepts and Design Rules 72.2.3 Thermal Constraints 212.2.4 Electrical Constraints 232.2.5 Device Layouts of Photoconductive Devices 352.2.6 Device Layouts of p-i-n Diode-Based Emitters 472.3 Principles of Electronic THz Generation 532.3.1 Oscillators with Negative Differential Conductance 542.3.2 Multipliers (Schottky Diodes, Hetero-Barrier Varactors) 562.3.3 Plasmonic Sources 58References 613 Principles of Emission of THzWaves 69Luis Enrique Garcya Munoz, Sascha Preu, Stefan Malzer, Gottfried H. Döhler, Javier Montero-de-Paz, Ramón Gonzalo, David González-Ovejero, Daniel Segovia-Vargas, Dmitri Lioubtchenko, and Antti V. Räisänen3.1 Fundamental Parameters of Antennas 693.1.1 Radiation Pattern 693.1.2 Directivity 713.1.3 Gain and Radiation Efficiency 713.1.4 Effective Aperture Area and Aperture Efficiency 723.1.5 Phase Pattern and Phase Center 723.1.6 Polarization 723.1.7 Input Impedance and Radiation Resistance 723.1.8 Bandwidth 733.2 Outcoupling Issues of THz Waves 733.2.1 Radiation Pattern of a Dipole over a Semi-Infinite Substrate 753.2.2 Radiation Pattern of a Dipole in a Multilayered Medium 793.2.3 Anomalies in the Radiation Pattern 823.3 THz Antenna Topologies 843.3.1 Resonant Antennas 853.3.2 Self-Complementary Antennas 873.4 Lenses 903.4.1 Lens Design 903.5 Techniques for Improving the Performance of THz Antennas 933.5.1 Conjugate Matching Technique 933.5.2 Tapered Slot Antenna on Electromagnetic Band Gap Structures 993.6 Arrays 1073.6.1 General Overview and Spectral Features of Arrays 1073.6.2 Large Area Emitters 113References 1574 Propagation at THz Frequencies 160Antti V. Räisänen, 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-Paz4.1 Helmholtz Equation and Electromagnetic Modes of Propagation 1604.2 THz Waveguides 1674.2.1 Waveguides with a Single Conductor: TE and TM Modes 1684.2.2 Waveguides with Two or More Conductors: TEM and Quasi-TEM Modes 1734.2.3 Waveguides with No Conductor: Hybrid Modes 1774.3 Beam Waveguides 1834.3.1 Gaussian Beam 1834.3.2 Launching and Focusing Components: Horns, Lenses, and Mirrors 1874.3.3 Other Components Needed in Beam Waveguides 1934.3.4 Absorbers 1954.3.5 Modeling Horns Using Mode Matching 1954.3.6 Multimode Systems and Partially Coherent Propagation 1994.3.7 Modeling Techniques for THz Propagation in THz Systems 2014.4 High Frequency Electric Characterization of Materials 2024.4.1 Drude Model 2034.4.2 Lorentz–Drude Model 2044.4.3 Brendel–Bormann Model 2054.5 Propagation in Free Space 2054.5.1 Link Budget 2054.5.2 Atmospheric Attenuation 206References 2075 Principles of THz Direct Detection 212Elliott R. Brown, and Daniel Segovia-Vargas5.1 Detection Mechanisms 2125.1.1 E-Field Rectification 2135.1.2 Thermal Detection 2155.1.3 Plasma-Wave, HEMT, and MOS-Based Detection 2205.2 Noise Mechanisms 2235.2.1 Noise from Electronic Devices 2235.2.2 Phonon Noise 2255.2.3 Photon Noise with Direct Detection 2275.3 THz Coupling 2305.3.1 THz Impedance Matching 2305.3.2 Planar-Antenna Coupling 2315.3.3 Exemplary THz Coupling Structures 2325.3.4 Output-Circuit Coupling 2355.4 External Responsivity Examples 2355.4.1 Rectifiers 2355.4.2 Micro-Bolometers 2365.5 System Metrics 2395.5.1 Signal-to-Noise Ratio 2395.5.2 Sensitivity Metrics 2405.6 Effect of Amplifier Noise 2435.7 A Survey of Experimental THz Detector Performance 2445.7.1 Rectifiers 2465.7.2 Thermal Detectors 2475.7.3 CMOS-Based and Plasma-Wave Detectors 249References 2506 THz Electronics 254Michael Feiginov, Ramón Gonzalo, Itziar Maestrojuán, Oleg Cojocari, Matthias Hoefle, and Ernesto Limiti6.1 Resonant-Tunneling Diodes 2546.1.1 Historic Introduction 2546.1.2 Operating Principles of RTDs 2556.1.3 Charge-Relaxation Processes in RTDs 2566.1.4 High-Frequency RTD Conductance 2596.1.5 Operating Principles of RTD Oscillators 2606.1.6 Limitations of RTD Oscillators 2616.1.7 Overview of the State of the Art Results 2646.1.8 RTD Oscillators versus Other Types of THz Sources 2656.1.9 Future Perspectives 2656.2 Schottky Diode Mixers: Fundamental and Harmonic Approaches 2656.2.1 Sub-Harmonic Mixers 2676.2.2 Circuit Fabrication Technologies 2706.2.3 Characterization Technologies 2726.2.4 Advanced Configuration Approach 2766.2.5 Imaging Applications of Schottky Mixers 2776.3 Solid-State THz Low Noise Amplifiers 2786.3.1 Solid-State Active Devices and Technologies for Low Noise Amplification 2806.3.2 Circuit and Propagation Issues for TMIC 2826.3.3 Low Noise Amplifier Design and Realizations 2846.3.4 Perspectives 2876.4 Square-Law Detectors 2886.4.1 Characterization and Modeling of Low-Barrier Schottky Diodes 2896.4.2 Design of Millimeter-Wave Square-Law Detectors 2916.5 Fabrication Technologies 2926.5.1 Overview of Fabrication Approaches of Schottky Structures for Millimeter-Wave Applications 2936.5.2 Film-Diode Process 296References 2997 Selected Photonic THz Technologies 304Cyril C. Renaud, Andreas Stöhr, Thorsten Goebel, Frédéric Van Dijk, and Guillermo Carpintero7.1 Photonic Techniques for THz Emission and Detection 3047.1.1 Overall Photonic System 3047.1.2 Basic Components Description 3067.1.3 Systems Parameters, Pulsed versus CW 3077.2 Laser Sources for THz Generation 3097.2.1 Pulsed Laser Sources 3097.2.2 Continous Wave (CW) Sources 3127.2.3 Noise Reduction Techniques 3147.2.4 Photonic Integrated Laser Sources 3157.3 Photodiode for THz Emission 3207.3.1 PD Limitations and Key Parameters 3207.3.2 Traveling Wave UTC-PD Solution 3227.4 Photonically Enabled THz Detection 3247.4.1 Pulsed Terahertz Systems 3257.4.2 Optically Pumped Mixers 3287.5 Photonic Integration for THz Systems 3317.5.1 Hybrid or Monolithic Integrations 3327.5.2 Monolithic Integration of Subsystems 3337.5.3 Foundry Model for Integrated Systems 334References 3358 Selected Emerging THz Technologies 340Christian Damm, Harald G. L. Schwefel, Florian Sedlmeir, Hans Hartnagel, Sascha Preu, and Christian Weickhmann8.1 THz Resonators 3408.1.1 Principles of Resonators 3418.1.2 Introduction to WGM Resonators 3438.1.3 Evanescent Waveguide Coupling to WGMs 3458.1.4 Resonant Scattering in WGM Resonators 3468.1.5 Nonlinear Interactions in WGM 3498.2 Liquid Crystals 3508.2.1 Introduction 3508.2.2 Characterization 3578.2.3 Applications 3658.3 Graphene for THz Frequencies 3678.3.1 Theory and Material Properties 3678.3.2 Applications 373References 377Index 383