THZ identification for defense and security purposes: identifying materials, substances, and items

✍ Scribed by coll.

• Year: 0
• Tongue: English
• Leaves: 229
• Category: Library

✦ Table of Contents

Contents......Page 8
Preface......Page 6
1. Introduction......Page 12
2.1. Nature of electromagnetism......Page 14
2.2. Electric fields......Page 15
2.3. Magnetic fields......Page 19
2.4. Static and dynamic fields......Page 22
2.5. Maxwell’s equations......Page 23
2.6. Coulomb’s law......Page 24
2.7. Gauss’s law......Page 26
2.8. Poisson’s equation......Page 28
2.9. Electrical properties of materials......Page 29
2.10. Conductors......Page 30
2.11. Resistance......Page 32
2.12. Dielectrics......Page 33
2.13. Magnetostatics......Page 37
2.14. Dynamic fields......Page 42
References......Page 48
3. Mathematical Methods of Identification......Page 50
3.1.1. General approach......Page 60
3.1.2. Nonlinear Least Squares Regression (NLSR)’s definition......Page 65
3.2. Developing a model: Example......Page 66
3.3. Validation of the created model......Page 68
3.4.1. General structure model......Page 71
3.5.2. Process simulation and identification......Page 73
References......Page 75
4. Physics of Producing and Detecting THz Waves......Page 78
4.1. Interaction of THz radiation with matter......Page 79
4.1.1. Photoconductive THz generation: Photoconductive emitters......Page 82
4.1.1.1. Example......Page 86
4.1.2. Photoconductive detectors......Page 87
4.2. Nonlinear optical pulse generation and detection......Page 88
4.2.1. Semiconductor materials......Page 94
4.2.2. Inorganic electro-optical compounds......Page 95
4.2.3. Organic electro-optical compounds......Page 96
4.2.5. Semiconductors and inorganic compounds for detectors......Page 99
4.2.6. Organic crystals......Page 106
References......Page 107
5.1. THz sources......Page 108
5.1.1.1. Example: Electron beam THz source......Page 112
5.1.1.3. Source of radiation......Page 113
5.1.1.5. Results......Page 114
5.1.2. Semiconductor sources of THz radiation......Page 115
5.1.2.1. Example: Electrically pumped photonic-crystal THz laser......Page 116
5.1.3. Continuous wave sources......Page 119
5.1.3.1. Example: Photomixer as CW, design features......Page 120
5.2. THz detectors......Page 123
5.2.1. Quantum superlattice as a THz detector......Page 126
5.2.1.1. Example: THz detector based on layered superlattice......Page 130
5.2.1.2. Resonant detector based on lateral superlattice......Page 131
5.2.1.3. Responsivity of the resonant detector......Page 133
5.3. Processing electronics......Page 135
5.3.1.1. The active multiplier chain......Page 136
5.3.1.2. Terahertz source evaluation......Page 139
5.4. Imaging using THz radiation......Page 140
5.4.1. Imaging considerations, measurement time and pulse signal-to-noise ratio......Page 141
5.4.2. Parametric images......Page 143
5.4.3. Image spatial resolution capabilities......Page 144
5.4.4. Safety measures for THz radiation......Page 151
References......Page 152
6. Electronics for Portable THz Devices......Page 154
References......Page 157
7. THz Applications......Page 158
7.1. THz imaging of nonmetallic structures......Page 159
7.1.1. Identification of tablet structure......Page 160
7.1.2. Interferometry for Terahertz imaging — a possible solution......Page 161
7.1.3. Results for the example......Page 170
7.2. Mobile THz systems......Page 174
7.2.1. Example: Mobile security surveillance system......Page 175
7.2.2. Example: Compact THz system......Page 178
7.3. THz identification of explosives......Page 180
7.3.1.2. Sensor set-up and operation......Page 182
7.3.2. Recent improvements of explosives identification......Page 187
7.4. THz identification of concealed weapons......Page 188
7.4.1. Image construction......Page 191
7.4.2. Additional improvements for identification of metal objects......Page 193
7.5. THz identification of illicit substances......Page 197
7.6. Prospects and conclusions......Page 199
References......Page 201
8. Medical and Other Applications of THz Radiation......Page 204
8.1. Data analysis — Example: Wavelet analysis......Page 207
8.1.1. Calculation of refractive index (for the Example)......Page 208
8.1.2. Calculation of absorption coefficient (for the Example)......Page 209
8.1.3. Results for the Example......Page 210
8.2. Dermatology......Page 212
8.3. Hard tissues diagnostics (dentistry, surgery, etc.)......Page 215
8.4. THz characterization of biological and inorganic material (hydrated and anhydrous)......Page 218
8.4.1. Modeling of water intermolecular structure......Page 219
8.4.1.1. THz spectroscopy of hydrated and anhydrous substances......Page 222
8.4.1.2. Conclusions for the examples and theory......Page 226
References......Page 227
Index......Page 228