The Optics Encyclopedia: Basic Foundations and Practical Applications

Thomas G. Brown.
Wiley-VCH, 2004.

TABLE OF CONTENTS

ÁËÎÊ_Ò V O L. I Amplifiers, Optical - Fourier and Other Transform Methods ÁËÎÊ_× AMPLIFIERS, OPTICAL 1 0 KEYWORDS: laser amplifiers; semiconductor optical amplifiers; rare-earth-doped fiber amplifiers; * fiber Raman amplifiers; fiber Brillouin amplifiers; preamplifiers; in-line repeater * amplifiers; booster amplifiers. 1 Introduction 2 2 Fundamental Properties of Laser Amplifiers 3 2.1 Stimulated and Spontaneous Transitions 3 2.2 Small-signal Gain and Bandwidth 5 2.3 Gain Saturation 5 2.4 Noise 6 3 Features of Various Types of Optical Amplifiers 9 3.1 Semiconductor Optical Amplifier 9 3.2 Rare-earth Ion-doped Fiber Amplifier 13 3.3 Fiber Raman Amplifier 14 3.4 Fiber Brillouin Amplifier 15 2 Amplifiers, Optical 4 System Applications of Optical Amplifiers 16 4.1 Preamplifier, In-line Repeater, and Booster Amplifier 16 4.2 Signal-to-noise Ratio in a Cascaded Linear Amplifier Chain 17 4.3 Amplifiers for Advanced Photonic Networks 19 4.3.1 Wideband DFAs for WDM Systems 19 4.3.2 Fiber Raman Amplifiers for Ultrabroadband Amplification 21 4.3.3 Semiconductor Optical Amplifiers for All-optical Signal Processing 21 5 Conclusion 23 Acknowledgment 23 Glossary 23 References 24 Further Reading 25 ÁËÎÊ_× ASTRONOMICAL TELESCOPES AND INSTRUMENTATION 27 0 KEYWORDS * astronomy; telescopes; instrumentation; adaptive optics; very large telescopes; * spectrographs. 1 Astronomical Telescopes 28 1.1 Introduction 28 1.2 History 29 1.3 Optical Designs of Telescopes 30 1.4 Calculating Optics 32 1.5 Making, Testing, and Supporting Mirrors 33 1.6 Telescope Mountings 34 1.7 Active Optics 36 1.8 Enclosures of Telescope 36 1.9 Examples of Telescopes 37 1.10 Special-purpose Telescopes 40 1.11 Seeing 42 1.12 Adaptive Optics 42 2 Attached Instrumentation 45 2.1 Detectors 46 2.2 Imaging 46 2.3 Polarimetry 46 2.4 Spectroscopy 47 2.5 Multipurpose Instruments 48 3 Observatory Conditions 49 4 Observing Styles 49 Glossary 49 References 50 Further Reading 51 ÁËÎÊ_× ATMOSPHERIC OPTICS 53 0 KEYWORDS * sky colors; mirages; green flash; coronas; rainbows; the glory; sun dogs; halos; visibility. 1 Introduction 54 2 Color and Brightness of Molecular Atmosphere 55 2.1 A Brief History 55 2.2 Molecular Scattering and the Blue of the Sky 57 2.3 Spectrum and Color of Skylight 58 2.4 Variation of Sky Color and Brightness 59 2.5 Sunrise and Sunset 62 3 Polarization of Light in a Molecular Atmosphere 63 3.1 The Nature of Polarized Light 63 3.2 Polarization by Molecular Scattering 64 4 Scattering by Particles 66 4.1 The Salient Differences between Particles and Molecules: Magnitude of Scattering 66 4.2 The Salient Differences between Particles and Molecules: Wavelength Dependence of Scattering 67 4.3 The Salient Differences between Particles and Molecules: Angular Dependence of Scattering 68 4.4 The Salient Differences between Particles and Molecules: Degree of Polarization of Scattered Light 69 4.5 The Salient Differences between Particles and Molecules: Vertical Distributions 70 5 Atmospheric Visibility 71 6 Atmospheric Refraction 73 6.1 Physical Origins of Refraction 73 6.2 Terrestrial Mirages 73 6.3 Extraterrestrial Mirages 76 6.4 The Green Flash 77 7 Scattering by Single Water Droplets 78 7.1 Coronas and Iridescent Clouds 78 7.2 Rainbows 80 7.3 The Glory 82 8 Scattering by Single Ice Crystals 83 8.1 Sun Dogs and Halos 83 9 Clouds 86 9.1 Cloud Optical Thickness 86 9.2 Givers and Takers of Light 87 Glossary 89 References 90 Further Reading 90 ÁËÎÊ_× BIOMEDICAL IMAGING TECHNIQUES 93 0 KEYWORDS * biomedical imaging; projection imaging; emission imaging; reflection imaging; digital * imaging; imaging in radiation therapy; new imaging modalities; image detail. 1 Radiation as a Diagnostic Probe 95 2 X-ray Transmission Imaging 96 2.1 Nature and Production of X rays 96 2.2 Interactions of X rays 98 2.3 Transmission Radiography 101 2.4 X-ray Detectors 103 2.5 X-ray Angiography 106 2.6 Digital Subtraction Radiography 107 3 X-ray Tomography 108 3.1 Analog Tomography 109 3.2 Computed Tomography 109 4 Ultrasound Imaging 114 4.1 Principles 114 4.2 Phased Arrays 117 4.3 Ultrasound Flow Imaging 118 4.4 Ultrasound Tissue Characterization 119 5 Nuclear Imaging 120 5.1 Radiopharmaceuticals 120 5.2 Scintillation Camera 122 5.3 Single Photon Emission Computed Tomography 123 5.4 Positron Emission Tomography 124 6 Magnetic Resonance Imaging 125 6.1 Signal Generation 126 6.2 Signal Localization 128 6.3 Flow Imaging 129 6.4 Functional MRI 130 7 Laser Optical Imaging 130 8 Electrical Impedance Tomography 131 9 Imaging Spontaneously Emitted Radiation 132 9.1 Infrared Thermography 132 9.2 Microwave Thermography 133 9.3 Acoustothermometry 133 9.4 Electrical Source Imaging 133 9.5 Magnetic Source Imaging 134 10 Image Detail 134 11 Image Interpretation 135 12 Image Networking 137 13 Conclusions 138 Glossary 138 References 140 Further Reading 141 ÁËÎÊ_× CHARGED-PARTICLE OPTICS 143 0 KEYWORDS * Charged particles; ions; electrons; beam optics; beam transport; magnetic * spectrometers; magnetic spectrographs; mass analyzers; focussing and deflection; * lenses; accelerators; aberrations; matrix optics; ion sources; ray tracing; achromatic; * isochronous; phase space; emittance; space charge; brightness; perveance; Lorentz force. 1 Introduction 145 1.1 Consumer Devices 145 1.2 Industrial Processes 145 1.3 Medical Diagnostics and Therapy 146 1.4 Instrumentation for Basic Research and Industrial Development 146 1.5 Organizations and Conferences 146 1.6 History 147 1.7 Scope of This Article 147 2 Fundamentals 148 2.1 Single-particle Motion in Electric and Magnetic Fields 148 2.1.1 Lorentz Force and Equations of Motion 148 2.1.2 Coordinate Systems 149 2.2 Charged-particle Beams 150 2.2.1 Emittance and Brightness 150 2.2.2 Phase Space and Liouville's Theorem 151 2.3 Space Charge Perveance 152 3 Beam Production 153 3.1 Charged-particle Sources, Extraction Optics, Space-charge Limit 153 3.2 Electron Sources 154 3.3 Ion Sources 154 4 Beam Handling and Transport 156 5 Beam Acceleration 157 6 Focusing Devices 158 6.1 Einzel Lenses 158 6.2 Glaser Lenses and Magnetic Solenoids 160 6.3 Plasma and Liquid Lithium Lenses 163 6.4 Quadrupole Lenses 163 6.5 First-order Matrix Optics 164 6.5.1 Thin Lens and Drifts 164 6.5.2 Matrix Elements and Imaging Conditions 166 6.5.3 Waists versus Images, Telescopic Imaging 167 6.5.4 Beam Transport 168 7 Deflecting Systems 169 7.1 Magnetic Sectors 169 7.1.1 Qualitative Properties 169 7.1.2 First-order Matrix Optics 172 7.2 Electric Sectors 172 7.2.1 Qualitative Properties 172 7.2.2 First-order Matrix Optics 173 7.3 Crossed-field Devices 173 7.3.1 Qualitative Properties 173 7.3.2 First-order Matrix Optics 174 7.4 Spectrometers 174 7.4.1 Momentum Analysis 174 7.4.2 Mass Analysis 175 Purely Magnetic Deflections 175 Combined Magnetic and Electric Deflections 175 7.5 Achromats and Isochronous Systems 176 7.5.1 Time-of-flight Mass Spectrometers 178 7.5.2 Beam Transport Systems 178 7.5.3 Dispersion-matching or Energy-loss Spectrometers 178 8 Aberrations 178 8.1 Second-order Matrix Optics 179 8.1.1 Focusing Systems, Chromatic Aberrations 179 8.1.2 Deflecting Systems (Spectrometers) 180 8.1.3 Second-order Achromats 181 8.2 Third-order Matrix Optics 182 8.2.1 Focusing Systems, Spherical Aberrations 182 8.2.2 Gridded Electrostatic Lenses 182 8.3 Higher-order Optics 182 8.3.1 Matrix Methods 182 8.3.2 Ray-tracing Methods 183 Glossary 183 References 185 Further Reading 186 ÁËÎÊ_× COLOR VISION 187 0 KEYWORDS * color; vision; trichromacy; photopigments; color opponency; color-blindness; * adaptation; color constancy. 1 The Functions of Color Vision 188 2 The Stimulus for Color 188 3 Trichromacy 190 4 Color Opponency 191 5 Color Appearance 194 6 Contextual Influences on Color Vision 195 7 Color Constancy 197 8 Contributions of Color to Form and Motion Perception 198 9 Individual Differences in Color Vision 200 10 Color Deficiencies 201 Acknowledgment 202 Glossary 202 References 205 Further Reading 206 ÁËÎÊ_× COLORIMETRY 207 0 KEYWORDS * color matching; color matching functions; cone fundamentals; colorimetry; * photometry; trichromacy; univariance; cone spectral sensitivities; chromaticity diagrams; color, CIE. 1 Introduction 208 1.1 Trichromacy and Univariance 209 1.2 Color Matching 209 1.2.1 Maximum Saturation Method 210 1.2.2 Maxwell's Matching Method 211 1.2.3 Linearity and Additivity of Color Matches 212 1.2.4 Complex Stimuli 212 1.2.5 Transformability of CMFs 212 1.2.6 Specificity of CMFs 213 1.2.7 Existing CMFs 214 2 Cone Spectral Sensitivities 214 3 Factors that Influence Color Matches 215 3.1 Individual Differences 215 3.1.1 Lens Pigment 215 3.1.2 Macular Pigment 215 3.1.3 Photopigment Optical Density 215 3.1.4 Photopigment Variability 216 3.1.5 Color Deficiency 217 3.2 Changes with Eccentricity 217 3.3 Bleaching 217 3.4 Rod Influence 217 4 Color Spaces 218 4.1 Two- and Three-dimensional Color Spaces 218 4.2 Other Cone Spaces 219 4.2.1 Equal-luminance Cone Excitation Space 219 4.2.2 Cone Contrast Space 220 4.3 Uniform Color Spaces 220 5 Existing Color-matching Functions 221 5.1 CIE (1931) 2-deg CMFs 221 5.2 Judd, Vos-modified CIE 2-deg CMFs 221 5.3 Stiles & Burch (1955) 2-deg CMFs 221 5.4 Stiles & Burch (1959) 10-deg CMFs 221 5.5 CIE (1964) 10-deg CMFs 222 5.6 Luminance and the Luminosity Function, V(?) 222 6 Conclusion 222 Acknowledgments 223 Glossary 223 References 224 Further Reading 225 ÁËÎÊ_× DATA STORAGE, OPTICAL 227 0 KEYWORDS * optical data storage; optical recording; compact disks; digital versatile disks; optical * disks; optical memory; optical servos. 1 Inspiration for the Invention and Early Development 228 2 Data Marks and Spaces: The Information Carriers 229 3 Optical Data Storage Basic Principles 230 4 Commercial Media 231 5 Technology 239 5.1 Data Density and Spot Size 239 5.2 Thermal Recording 242 5.3 Frequency Response and Equalization 243 5.4 Effects of Defocus 245 5.5 Servo Optics 245 5.6 Feedback Sensors 247 5.7 Noise and Jitter 251 5.8 Data Coding and Formatting 252 5.9 Configurations for Optical Media 254 5.10 Laser Sources 254 6 Performance 258 7 Optical Data Storage for High-definition Television (HDTV) 259 8 Future Systems 266 Glossary 269 References 272 ÁËÎÊ_× DIODES, LIGHT-EMITTING 275 0 KEYWORDS: light-emitting diode; compound semiconductor; solid-state lighting; energy gap; * visible; LPE; MOVPE. 1 Introduction 277 2 Basic Characteristics and Designs 279 2.1 p -- n Junction and Current -- voltage Characteristics 279 2.2 Emission Wavelength 281 2.3 Efficiency 281 2.3.1 Internal Efficiency 281 Radiative and Nonradiative Recombination 281 Direct and Indirect Energy Gap 282 Direct -- indirect Transition 283 Isoelectronic Impurities 285 2.3.2 Carrier Confinement 285 Homojunctions 285 Single Heterostructures 288 Double Heterostructures 288 Quantum Wells 288 2.3.3 Extraction Ratio 289 Light Extraction from an LED with an Absorbing Substrate 289 Light Extraction from an LED with a Transparent Substrate 291 2.3.4 Figures of Merit for Efficiency 292 External Quantum Efficiency and Power Efficiency 292 Luminous Efficiency 292 2.3.5 Effect of Temperature 293 2.3.6 Effect of Current 294 2.4 Reliability 294 2.4.1 Radiation- and Current-enhanced Degradation 295 2.4.2 Package-related Degradation 295 2.5 Semiconductor Material Issues 296 2.5.1 Energy Gap 296 2.5.2 Lattice Matching 297 2.5.3 Substrates 298 2.5.4 Dopants and Impurity Incorporation 299 3 Visible Emitters 299 3.1 Visible LED Technologies 299 3.1.1 GaAsP and GaAsP : N 301 3.1.2 GaP : N, GaP : (Zn,O), and GaP 301 3.1.3 AlxGa1-xAs 302 3.1.4 AlGaInP 302 3.1.5 AlGaInN 305 3.1.6 White LEDs 306 3.1.7 Polymeric and Molecular Organic LEDs 307 3.2 Applications 308 3.2.1 Instrument and Computer 308 3.2.2 Consumer Electronics 308 3.2.3 Large-area Displays 310 3.2.4 Vehicular Lighting 310 3.2.5 Traffic Signaling 310 3.2.6 Trends and Future Development 310 4 Infrared Emitters 311 4.1 Infrared LED Technologies 311 4.1.1 GaAs * Si and AlGaAs * Si 311 4.1.2 AlGaAs 313 4.1.3 Small-emission-area AlGaAs and InGaAsP 313 4.2 Current-voltage Characteristics 314 4.3 Applications for Infrared Emitters 314 4.3.1 Remote Controls 314 4.3.2 Optocouplers 314 4.3.3 Sensors 315 4.3.4 Optical Communications 315 4.3.5 Trends and Future Developments 315 5 Manufacturing Technology 315 5.1 Substrate Growth 316 5.2 Epitaxial Growth 316 5.2.1 Epitaxial Growth Overview 316 5.2.2 Liquid-phase Epitaxy 317 5.2.3 Vapor-phase Epitaxy 317 5.2.4 Metal-organic Vapor-phase Epitaxy 317 5.3 Wafer Fabrication 318 5.3.1 Junction Formation 318 5.3.2 Ohmic Contact Formation 318 5.3.3 Dicing 319 5.4 Assembly 319 5.4.1 Die Attachment 319 5.4.2 Wire Bonding 319 5.4.3 Encapsulation and Packaging 320 6 History of LED Development 321 6.1 Infrared LEDs 321 6.2 Visible LEDs 321 Glossary 322 References 323 Further Reading 325 ÁËÎÊ_× DISPLAY TECHNOLOGY 327 0 KEYWORDS * cathode ray tube; flat-panel display; plasma display; electroluminescent display; liquid * crystal display; active matrix display; microparticle-based display; projection display. 1 Introduction 329 2 Display Categories 329 3 Cathode-ray Tubes (CRTs) 332 3.1 Color CRTs 333 3.2 Electron Optics 334 3.3 Phosphors 335 3.4 Trends 336 4 Flat-panels Matrix Addressing 336 4.1 Light-generating (Active) Displays 337 4.1.1 Gas Discharge 338 AC Plasma Displays 339 Plasma Display Addressing 341 Remaining Problems for Plasma Displays 342 4.1.2 Cathodoluminescence 343 Vacuum Fluorescence Displays (VFDs) 343 Field-emission Displays (FEDs) 344 4.1.3 Electroluminescence 346 Visible Light-emitting Diodes (LEDs) 346 Organic and Polymer Light-emitting Diodes 349 Electroluminescence in Inorganic Materials 351 4.2 Light-modulating (Passive) Displays 352 4.2.1 Liquid Crystal Displays 353 Fundamental Operation 353 Simple Matrix-addressed LCDs 354 Novel Addressing Schemes for Direct-addressed STN LCDs 356 4.2.2 Reflective LCDs for Low-power Systems 356 Reflective LCDs with Polarisers 356 Zero-polarizer Reflective LCDs 356 4.2.3 Bistable Liquid Crystal Devices 359 4.2.4 Active Matrix-addressed Liquid Crystal Displays (AMLCDs) 360 Fundamental Properties 360 Manufacturing Issues 361 Viewing Angle Improvements 362 System Performance 364 Plasma-addressed Liquid Crystal Displays 364 4.2.5 Microparticle-based Displays 365 Electrophoretic Displays 365 Rotating Ball Displays (Gyricon) 367 5 Projection Technologies 368 5.1 Projection CRT 368 5.2 Liquid Crystal Projection 369 5.2.1 Transmissive Projection LCDs 369 5.2.2 Reflective Projection LCDs 370 5.3 Micro Mechanical Light Valve Projection 370 Glossary 371 References 372 Further Reading 373 ÁËÎÊ_× ELECTRODYNAMICS 375 0 KEYWORDS * electromagnetism; Maxwell's equations; radiation; diffraction; electromagnetic * waves; dispersion. 1 Introduction 377 2 Units, Symbols, and Conventions 379 Complex numbers 379 Harmonic quantities 379 Time averages 379 Fourier integrals 380 3 The Maxwell Equations in Vacuum in Differential and Integral Form 380 3.1 Coulomb's Law 380 3.2 Amp `ere -- Maxwell Law 380 3.3 Faraday's Law 382 3.4 Law of Magnetic Flux 385 3.5 Limitations 385 4 Material Media, Constitutive Relations, Boundary Conditions, and Simple Dielectric and Magnetic Properties of Matter 385 4.1 Macroscopic Maxwell Equations 385 4.2 Constitutive Relations 386 4.3 Boundary Conditions at Interfaces between Different Media 388 4.4 Frequency Dependence of the Dielectric Constant 389 4.5 Causality and Analytic Properties of ?(?) 392 5 Electrostatic and Magnetostatic Energies, Capacitance, and Inductance 395 5.1 Electrostatic Energy 395 5.2 Capacitance and Coefficients of Capacitance 396 5.3 Magnetostatic Energy 396 5.4 Inductance 397 5.5 Symmetry and Reciprocity Properties 398 6 Conservation Laws for Energy and Momentum 399 6.1 Poynting's Theorem of Conservation of Electromagnetic Energy 399 6.2 Conservation of Momentum, Maxwell Stress Tensor, and Radiation Pressure 400 7 Harmonic Sources and Fields 402 7.1 Wave Equations and their Solutions for the Fields 402 7.2 Radiation by Dipole Sources 403 8 Plane Waves 404 8.1 Basic Properties 404 8.2 Polarization, Stokes Parameters 405 8.3 Reflection and Refraction at a Plane Interface between Two Linear Media 407 9 Diffraction 408 9.1 Interference as Primordial Diffraction 409 9.2 Scalar Diffraction Theory -- Kirchhoff, Rayleigh, Sommerfeld 410 9.3 Vectorial Diffraction Theory 412 9.4 Further Reading 413 10 Special Relativity and Covariant Electrodynamics 413 10.1 Summary of Results in Special Relativity 413 10.2 Relativistic Formulation of Electrodynamics 415 Glossary 417 References 420 Further Reading 421 ÁËÎÊ_× ELECTROMAGNETIC RADIATION 423 * EMISSION AND PROPAGATION 0 KEYWORDS: electromagnetic radiation; Maxwell equations; Hertzian dipole; multipole radiation; * Lienard -- Wiechert potentials; synchrotron radiation; Fresnel formula; surface plasmons; Cherenkov radiation. 1 Introduction 424 2 The Fundamental Equations 425 2.1 Maxwell -- Lorentz Equations in Vacuum 425 2.2 The Conservation Laws 426 3 Waves in Vacuum 428 3.1 Plane Waves 428 3.2 Monochromatic Waves; the Gaussian Focus 430 4 General Integration Theory 432 4.1 Integration of the Maxwell Equations -- The Scalar and Vector Potentials 432 4.2 Radiation by a Hertzian Dipole -- The Larmor Formula 435 4.3 Radiation by a Confined Source 437 4.4 Multipole Radiation 439 4.5 Radiation by Half-wave Antenna 441 5 Radiation by a Moving Point Charge 442 5.1 The Lienard -- Wiechert Potentials 442 5.2 The Radiated Power 444 6 Synchrotron Radiation 445 6.1 The Fields 445 6.2 The Radiated Power 447 7 Radiation Reaction 449 8 The Maxwell Equations in Material Media 453 8.1 The Maxwell Equations 453 8.2 General Integration Theory 455 8.3 Remarks on the Conservation Laws 455 9 Plane Waves in Material Media 456 9.1 Plane Waves in Isotropic Media 456 9.2 Plane Waves in Anisotropic Media 457 9.3 Chiral Media 458 10 Propagation in Layered Media 459 10.1 The Fresnel Formulas 459 10.2 Transparent Media, Total Reflection, Brewster's Angle 460 10.3 Surface Plasmons 461 10.4 Reflection by a Bilayer 463 10.5 Guided Waves in Layered Media 464 10.6 Rectangular Waveguides 465 11 Radiation by a Dipole above a Half-Space 466 12 Cherenkov Radiation and Stopping Power 469 12.1 Cherenkov Radiation 469 12.2 Stopping Power 473 Glossary 476 References 477 ÁËÎÊ_× ELECTRON DIFFRACTION 479 0 KEYWORDS: electron diffraction; electron microscopy; scattering theory; crystal-structure analysis; * thin films; surface structure; crystal defects; gas molecules. 1 Introduction 480 2 Theoretical Basis 481 3 Electron Diffraction in Electron Microscopes 487 4 Identifying Unknown Phases 493 5 Structure Analysis 493 6 Convergent-beam Electron Diffraction 496 7 Energy Losses and Secondary Radiations 497 8 Diffraction from Imperfect Crystals 499 9 Electron-diffraction Studies of Surfaces 501 10 Diffraction by Gases and Amorphous Material 503 Glossary 505 References 506 Further Reading 508 ÁËÎÊ_× ELECTRO-OPTIC DEVICES 511 0 KEYWORDS: electro-optic effect; nonlinear optics; light modulation; optical communications; * nonlinear optical materials; optical waveguides; anisotropic materials. 1 Introduction 512 2 Crystal Optics and the Index Ellipsoid 513 3 The Electro-optic Effect 515 3.1 The Linear Electro-optic Effect 516 3.2 Eigenpolarizations and Phase Velocity Indices of Refraction 519 4 Modulator Devices 521 4.1 Bulk Device Configurations 522 4.2 Modulation of Light Parameters 523 4.2.1 Phase Modulation 523 4.2.2 Polarization Modulation (Dynamic Retardation) 525 4.2.3 Amplitude Modulation 526 4.2.4 Frequency Modulation 529 4.2.5 Scanners/Deflectors 530 5 Design Considerations 533 5.1 Materials 533 5.2 Transit Time Limitations 536 5.3 Device Types 536 5.3.1 Bulk Modulators 536 5.3.2 Traveling Wave Modulators 537 5.3.3 Integrated Optical Modulator 538 5.3.4 Optical Fiber Modulators 539 5.4 Device Packaging 539 5.5 Space Applications 539 6 Performance Criteria 539 6.1 Modulation Bandwidth 539 6.2 Power per Unit Bandwidth (Specific Energy) 540 6.3 Extinction Ratio 540 6.4 Maximum Frequency Deviation 541 6.5 Percent Modulation 541 6.6 Degree of Modulation 541 6.7 Modulation Efficiency 541 6.8 Optical Insertion Loss 542 7 Applications 542 Glossary 542 Acknowledgment 544 References 544 ÁËÎÊ_× ELECTRO-OPTIC IMAGING 549 0 KEYWORDS: UV imaging; low-light-level imaging; image-intensifier tubes; short-wave infrared * vision (SWIR); thermal IR vision; IR detectors; cooling systems; range performance. 1 Introduction 551 2 UV Imaging 552 2.1 Physical Properties of the UV Spectral Region 553 2.2 Two-dimensional UV Cameras 553 2.2.1 UV Optics 554 2.2.2 UV Sensors 555 The ''UV-i-CCD'' Method 556 UV-to-VIS Converters 556 Back-illuminated CCDs 556 UV-enhanced Photodiode Arrays 557 2.3 Applications 557 2.3.1 Missile Warning 558 2.3.2 Covert Operations 558 2.3.3 Penetration of Fog, Heavy Rain, and Snow 558 3 Imaging in the Near and Short-wave Infrared and at Very Low Light Levels 558 3.1 Physical Properties of the Visible and the Near and Short-wave Infrared Regions 559 3.2 Imaging Techniques 561 3.2.1 Active Infrared Imaging and Gated Viewing 561 Active Infrared Imaging 561 Gated Viewing 562 3.2.2 I2 Tubes 564 3.2.3 Imaging in the SWIR Region 566 3.3 Applications 566 3.3.1 Passive Night Vision 566 3.3.2 Fog Penetration 567 4 Vision in the Thermal Infrared 568 4.1 Planck's Law and Atmospheric Transmission 568 4.1.1 Implications of Planck's Law on the Design of Electro-optical Sensors 568 4.1.2 Atmospheric Transmission 569 4.1.3 Applications 570 4.2 Infrared Optics 570 4.2.1 Antireflection Coating 571 4.2.2 Infrared Optics Design 571 4.3 Infrared Detectors 572 4.4 Cooling 572 4.4.1 Thermoelectric Cooling 573 4.4.2 Joule -- Thomson Cooling 574 4.4.3 Stirling-engine Cooling 574 4.5 Infrared Systems 576 4.5.1 Scanning Systems 576 4.5.2 Staring Systems 577 4.6 Uncooled Systems 577 4.7 System Performance 580 4.7.1 Noise-equivalent Temperature Difference, NETD 580 4.7.2 Minimum Resolvable Temperature Difference, MRTD 580 4.7.3 Range Performance 582 Acknowledgment 582 Glossary 583 References 584 Further Reading 585 ÁËÎÊ_× ELECTROPHOTOGRAPHIC COPYING AND PRINTING (XEROGRAPHY) 587 0 KEYWORDS * electrophotography; copiers; printers; laser raster output scanning; light emitting diode * array; optical scanner. 1 Introduction 588 2 Historical Perspective 589 3 Electrophotographic Process Steps 589 4 Optical Imaging Copiers 591 4.1 Moving Optics 591 4.1.1 Fixed Platen Optical Imaging 591 4.1.2 Moving Platen Optical Imaging 592 4.2 Full-frame Flash Optics 594 5 Printers and Digital Copiers 595 5.1 Polygon ROS Imagers 595 5.1.1 Laser Light Source 596 5.1.2 Motor-polygon Assembly 598 5.1.3 Optics 598 5.1.4 Electronics 600 5.2 LED Printbars 601 5.2.1 Substrate Circuit Board Assembly 602 5.2.2 Optics 603 5.2.3 Heat Sink 603 5.2.4 Electronics 603 6 Color Registration 604 7 Summary and Conclusion 606 Acknowledgment 606 Glossary 606 References 607 ÁËÎÊ_× ELLIPSOMETRY 609 0 KEYWORDS * ellipsometry; spectroscopic ellipsometry; ellipsometers; polarization; reflectometry; * optical properties; dielectric function; index of refraction; extinction coefficient; thin films; thickness. 1 Introduction 611 2 Measurement Principles 614 2.1 Polarization and the Optical Properties of Materials 615 2.2 Ellipsometry Measurement of a Single Interface 616 2.3 Ellipsometry Measurement of a One-layer Structure 618 2.4 Ellipsometry Measurement of a Multilayer Structure 620 3 Ellipsometer Designs 622 3.1 The Generic Ellipsometer Configuration 622 3.2 Manual Null Ellipsometers 624 3.3 Automatic Null Ellipsometers 625 3.4 Rotating Element Ellipsometers 626 3.5 Phase-modulation Ellipsometers 629 4 Specialized Techniques 631 4.1 Spectral Range * Infrared and Ultraviolet Extended Spectroscopic Ellipsometry 631 4.2 Spatial Resolution * Microellipsometry and Imaging Ellipsometry 633 4.3 Time Resolution * Real-time Spectroscopic Ellipsometry 635 5 Sample Considerations 637 5.1 Sample Structure, Inhomogeneity, and Nonuniformity 637 5.2 Sample Surface and Interface Nonidealities 639 6 Data Analysis 640 6.1 Static Spectroscopic Ellipsometry 641 6.2 Real-time Spectroscopic Ellipsometry 643 7 Application Examples 645 7.1 Static Samples 646 7.2 Dynamic Samples 652 8 Conclusions and Future Directions 663 Acronyms 664 Glossary 665 Acknowledgment 667 References 667 Further Reading 669 ÁËÎÊ_× FIBER OPTICS 671 0 KEYWORDS: optical fiber; glass; silica. 1 Introduction 673 2 Structure of Optical Fibers 674 2.1 Basic Structure 674 2.2 Multimode Fibers 675 2.3 Single-mode Fibers 675 2.4 Dispersion-modified Fibers 676 2.4.1 Dispersion-shifted Fibers 676 2.4.2 Nonzero Dispersion-shifted Fiber 676 2.4.3 Dispersion-flattened Fibers 677 2.5 Functional Fibers 677 2.5.1 Dispersion-compensating Fibers 677 2.5.2 Rare-earth-doped Fibers 677 2.5.3 Polarization-maintaining Fibers 678 3 Raw Materials and Production 678 3.1 Silica Fibers 678 3.1.1 Preform Production 678 Modified Chemical Vapor Deposition (MCVD) Method 679 Outside Vapor Deposition (OVD) Method 680 Vapor-Phase Axial Deposition (VAD) Method 680 Plasma Chemical Vapor Deposition (PCVD) Method 681 3.1.2 Fiber Drawing 681 3.2 Non-silica Fibers 681 3.2.1 Multicomponent Glass Fibers 681 3.2.2 Plastic Cladding Fibers 682 3.2.3 All-plastic Fibers 682 3.2.4 Infrared Fibers 683 4 Characteristics of Optical Fibers 684 4.1 Transmission Loss 684 4.2 Dispersion 685 4.2.1 Multimode Dispersion 685 4.2.2 Chromatic Dispersion 685 4.2.3 Polarization Mode Dispersion 686 4.3 Nonlinearity 686 5 Reliability of Optical Fibers 686 5.1 Mechanical Strength 686 5.2 Hydrogen-induced Loss Increase 687 5.3 Radiation-induced Loss Increase 687 6 Applications of Optical Fibers 689 6.1 Optical Fiber Cables 689 6.2 Fiber Connection Technologies 689 6.3 Optical Fiber Sensors 690 7 Future Prospects 691 7.1 New Fibers 691 Photonic Crystal Fiber (PCF) 691 Holey Fiber (HF) 691 Photonic Band-gap Fiber (PBGF) 691 7.2 New Systems 691 Soliton System 692 Code Division Multiplex (CDM) 692 Glossary 692 References 693 Further Reading 694 ÁËÎÊ_× FILTERS, OPTICAL 695 0 KEYWORDS: filters, theory; thin film interference; antireflection coatings; neutral attenuators; * reflection filters; cutoff filters; transmission filters; rejection filters; beam splitters; * correction filters; gain flattening filters. 1 Introduction 696 2 General Theory of Filters 697 2.1 Transmittance, Reflectance, Absorptance, and Scatter 697 2.2 Surface Reflection Effects 699 2.3 Transmission Filters in Series and in Parallel 699 2.4 Reflection Filters in Series 700 3 Physical Principles Used for the Construction of Filters 701 3.1 Absorption 701 3.2 Reflection 703 3.3 Interference in Thin Films 703 3.4 Holography 705 3.5 Fiber Bragg Gratings and Guided Mode Resonant Filters 706 3.6 Scattering 706 3.7 Diffraction 707 3.8 Interference of Polarized Light 709 4 Performance of Specific Filter Types 710 4.1 Antireflection Coatings 710 4.2 Neutral Attenuators 711 4.3 Narrow and Intermediate Bandwidth Reflectors 712 4.4 Broadband Reflectors 713 4.5 Short-wavelength Cutoff Filters 715 4.6 Long-wavelength Cutoff Filters 715 4.7 Narrowband Transmission Filters 715 4.8 Rejection Filters 717 4.9 Neutral and Color-selective Beam Splitters 718 4.10 Correction and Gain Flattening Filters 719 5 Specifying Filters 721 6 Concluding Remarks 723 Glossary 723 Further Reading 723 ÁËÎÊ_× FOURIER AND OTHER TRANSFORM METHODS 725 0 KEYWORDS: transforms; interferometry; coherence; fractional Fourier transform; tomography; * projection-slice theorem; nulling interferometry; volume rendering; Abel transform; * Hankel transform; Hartley transform; Radon transform. 1 Introduction 726 2 The Fourier Transform 726 3 Continuous versus Discrete Transforms 728 4 Some Common Transforms 730 5 The Laplace Transform 734 6 Convergence Conditions 735 7 Why Transforms are Useful 736 8 Fields of Application 737 9 The Hartley Transform 738 10 Multidimensional Transforms 740 11 The Hankel Transform 740 12 The Abel Transform 741 13 Tomography and the Radon Transform 743 14 Applications to Optics 744 Glossary 747 References 748 Further Reading 749 ÁËÎÊ_Ò V O L. II Geometric Optics - Luminescence ÁËÎÊ_× GEOMETRIC OPTICS 751 0 KEYWORDS: geometric optics; optical engineering; image formation; aberrations; imaging system 1 Introduction 753 2 Basic Concepts 753 2.1 Corpuscular Theory 753 2.1.1 Rays as Trajectories of Energetic Particles 753 2.1.2 Refractive Index, Color, and Dispersion 754 2.1.3 Fermat’s Principle and Optical Paths 754 2.1.4 Snell’s Law 754 2.2 Wave Theory 755 2.2.1 The Point Source 755 2.2.2 Geometrical Wave Fronts 755 2.2.3 Connection with Physical Optics 755 2.2.4 Significance in Imaging Systems 755 3 General Applications 755 3.1 Physical Optics 755 3.1.1 Wave-front Propagation 755 3.1.2 The Use of Ad Hoc Properties 756 3.1.3 Diffracted Rays 756 3.2 Radiometry 756 4 Imaging Systems: First Order 756 4.1 Objects and Images * Optical Spaces 756 4.2 Ideal Behavior * Collinear Mapping 757 4.3 Axially Symmetric Systems 757 4.3.1 Focal Systems and Gaussian Imagery 757 4.3.1.1 Cardinal Points 757 4.3.1.2 Gaussian Imagery 758 4.3.1.3 Gaussian Reduction 758 4.3.2 Afocal Systems 759 4.3.3 Ray Tracing and Paraxial Optics 759 4.3.4 Fields and Pupils 760 4.3.5 Marginal and Chief Rays 760 4.3.6 The Optical (Lagrange) Invariant 761 4.3.7 Numerical Aperture and the f Number 761 4.4 Systems with No Axial Symmetry 762 5 Imaging Systems * Aberrations 762 5.1 Aberrations as Departures from Ideal Behavior 762 5.2 Wave and Ray Aberrations 763 5.3 Monochromatic Aberrations 763 5.3.1 Expansions and Classification 763 5.3.2 Elementary (Third-order) Aberrations 763 5.3.2.1 Spherical Aberration 763 5.3.2.2 Coma 765 5.3.2.3 Astigmatism 766 5.3.2.4 Field Curvature 766 5.3.2.5 Distortion 766 5.4 Chromatic Aberrations 767 5.4.1 Elementary (Primary) Chromatic Aberrations 768 5.4.2 Chromatic Variation of Monochromatic Aberrations 768 5.5 The Control of Aberrations in Optical Design 768 Glossary 768 Further Reading ÁËÎÊ_× HOLOGRAPHY 773 0 KEYWORDS * imaging; phase; interference; wavefront reconstruction; metrology; nondestructive * testing; optical storage; displays; phase conjugation 1 Introduction 774 2 Holographic Principles 774 3 Mathematical Theory 778 4 The Rise of Modern Holography 780 5 Some Early Applications 782 5.1 Imaging Through Inhomogeneities Using Holographic Phase Conjugation 782 5.2 Complex Spatial Filtering 783 5.3 Hologram Interferometry 787 5.4 Holographic Optical Elements 789 6 Volume Holography 790 7 Display Holography 793 7.1 The Beginnings 793 7.2 The Denisyuk Hologram 793 7.3 The Benton Hologram 794 7.4 The Multiplex and Related Holograms 795 7.5 Construction of Commercial Display Holograms 796 8 Holography Today 797 Glossary 797 References 799 Further Reading 799 ÁËÎÊ_× IMAGE PROCESSING OF OPTICAL DATA 801 0 KEYWORDS * image enhancement; image restoration; image compression; low-level computer * vision; edge detection; image segmentation 1 Introduction 802 2 Creation and Representation of Digital Images 803 3 Application of Linear Algebra to Digital Image Processing 804 3.1 Linear Operators and Point Spread Functions 805 3.2 Different Bases of Image Expansion 805 3.3 Linear Image Compression 806 3.4 Tasks Accomplished by Linear Image Processing 807 4 Nonlinear Image Processing 807 4.1 Histogram Equalization 807 4.2 Thresholding 807 4.3 Probabilistic Approaches 810 5 Color Image Processing 810 6 Concluding Remarks 811 Glossary 811 References 813 Further Reading 813 ÁËÎÊ_× IMAGING DETECTORS. CHARGE-COUPLED DEVICES AND CMOS ACTIVE PIXEL SENSORS 815 0 KEYWORDS: charge-coupled device; active pixel sensor; CMOS-APS; visible imager; CCD. 1 Introduction 817 2 Charge Storage 819 2.1 Channel Potential 822 2.2 Charge Detection and Collection 823 3 Charge Transfer Process 825 4 Device Architecture 827 4.1 Linear Arrays 827 4.2 Area Arrays 828 4.2.1 CMOS Arrays 828 Camera-on-a-chip 828 Rolling Shutter 829 Snapshot Shutter 830 High Frame Rate Arrays 830 Other Arrays 831 4.2.2 CCD Arrays 832 Full-frame CCD 832 Frame-transfer CCD 833 Interline Transfer CCD 833 Orthogonal Transfer CCD 834 Time Delay and Integrate CCDs 834 Deep Depletion CCDs 834 CMOS/CCDs 836 4.3 Color CCDs and CMOS Arrays 837 4.4 Infrared Arrays 837 5 Pixels 838 5.1 CCD Pixels 838 5.1.1 Four Phase 838 5.1.2 Three Phase 838 5.1.3 Two Phase 840 5.1.4 Virtual Phase 841 5.1.5 Photon-counting CCDs 841 5.2 CMOS/APS Pixels 843 5.2.1 Three Transistor Cell 843 5.2.2 Four Transistor Cell 844 5.2.3 Other Cells 845 6 OutputAmplifiers 846 6.1 Floating Diffusion 846 6.2 Floating Gate 848 6.3 CMOS Column Amplifiers 848 7 Performance 851 7.1 Dark Current 851 7.1.1 MPP Operation 852 7.2 Charge Transfer Efficiency 854 7.3 Linearity 855 7.3.1 CCD 855 7.3.2 APS Linearity 856 7.4 Noise 856 7.4.1 Input Noise 858 7.4.2 CCD Readout Noise 858 7.4.3 APS Noise 859 7.4.4 Noise versus Readout Rate 860 7.5 Well Capacity and Dynamic Range 860 7.5.1 Antiblooming 863 7.6 Spectral Response 864 7.6.1 Front-illumination 865 7.6.2 Back Illumination 866 7.7 Modulation Transfer Function 867 8 Summary 869 Glossary 870 References 872 Further Reading 874 ÁËÎÊ_× INFORMATION PROCESSING, OPTICAL 877 0 KEYWORDS: optical information processing; optical imaging; optical pattern recognition; optical * security; optical spatial light modulators; optical neural computing; optical memory. 1 Introduction 878 2 Fourier-transform Property of Lenses 879 3 Filters 880 3.1 Correlation and Matched Filtering 880 3.2 Spatial Filter Development 882 3.3 Binary Phase-only Filters (BPOFs) 883 3.4 Optimum Filtering for Spatially Nonoverlapping Target and Scene Noise 884 4 Correlations 886 4.1 Classical Joint-transform Correlators 886 4.2 Nonlinear Joint-transform Correlators 888 5 Spatial Light Modulators (SLMs) 890 5.1 Capabilities of SLMs 891 5.2 SLM Performance Considerations 892 5.3 Photorefractive Materials and Devices 892 5.4 Liquid-crystal Light Valves 893 5.5 Liquid-crystal Television Displays (LCTVs) 894 5.6 Ferroelectric Liquid-crystal Spatial Light Modulators 895 5.7 Deformable-mirror Spatial Light Modulators 895 6 Acousto-optic Signal Processing 896 7 Optical Interconnections 898 8 OpticalMemory 899 9 Neural Networks 901 9.1 Overview of Neural Networks 901 9.2 Perceptron 902 9.3 Multilayer Perceptron 904 9.4 Associative Memory 904 9.5 Vector-matrix Architectures 905 9.6 Optical-correlator Neural Nets 906 9.7 Hologram-based Neural Nets 908 9.8 Hughes Programmable Multilayer Optical Neural Net 909 9.9 Learning in Multilayer Neural Nets 910 10 Conclusions 910 Acknowledgment 911 References 911 ÁËÎÊ_× INTERCONNECTIONS, OPTICAL 915 0 KEYWORDS: interconnections, optical; interconnections, electrical; waveguide; optical bus; * free-space optical interconnection; integrated optics; optical backplane; multiprocessor * systems; parallel processor systems. 1 Introduction 916 2 Limit of Electrical Interconnection 917 3 Potential of Optical Interconnection 918 4 Optical-interconnection Schemes 920 5 Optical-interconnection Hierarchy 921 6 Rack-to-rack Optical Interconnection 923 7 Board-to-board Optical Interconnection 923 8 Intraboard Optical Interconnection 928 9 Optical-interconnection Devices 930 10 Systems and Applications 931 11 Future Prospects 934 References 935 Further Reading 936 ÁËÎÊ_× INTERFEROMETRY937 0 KEYWORDS: interferometry; interference; interferometers; optical testing; optical metrology; * nondestructive testing. 1 Introduction 939 2 Interference and Coherence 940 2.1 Localization of Fringes 941 2.2 Coherence 941 3 Two-beam Interferometers 942 3.1 The Michelson Interferometer 942 3.2 The Mach–Zehnder Interferometer 943 3.3 The Sagnac Interferometer 943 4 Multiple-beam Interference 943 4.1 Fringes of Equal Chromatic Order 944 5 Measurement of Length 944 5.1 Electronic Fringe Counting 944 5.2 Heterodyne Interferometry 944 5.3 Two-wavelength Interferometry 945 5.4 Frequency-modulation Interferometry 946 5.5 Laser-feedback Interferometry 946 6 Optical Testing 946 6.1 Flat Surfaces 946 6.2 Homogeneity 947 6.3 Concave and Convex Surfaces 947 6.4 Prisms 947 6.5 Aspheric Surfaces 948 6.6 Optically Rough Surfaces 948 6.7 Shearing Interferometers 948 6.8 The Point-diffraction Interferometer 949 7 Fringe Analysis 949 7.1 Fringe Tracking and Fourier Analysis 949 7.2 Phase-shifting Interferometry 950 7.3 Determining Aberrations 951 8 Interference Microscopy 951 8.1 The Mirau Interferometer 951 8.2 The Nomarski Interferometer 951 8.3 White-light Interferometry 952 9 Interferometric Sensors 953 9.1 Laser–Doppler Interferometry 953 9.2 Fiber Interferometers 954 9.3 Rotation Sensing 955 10 Interference Spectroscopy 955 10.1 Etendue of an Interferometer 955 10.2 The Fabry–Perot Interferometer 955 10.3 Wavelength Measurements 957 10.4 Laser Linewidth 958 10.5 Fourier-transform Spectroscopy 958 11 Nonlinear Interferometers 959 11.1 Second-harmonic Interferometers 959 11.2 Phase-conjugate Interferometers 960 11.3 Measurement of Nonlinear Susceptibilities 961 12 Interferometric Imaging 961 12.1 The Intensity Interferometer 961 12.2 Heterodyne Stellar Interferometers 962 12.3 Stellar Speckle Interferometry 963 12.4 Telescope Arrays 963 13 Space-time and Gravitation 963 13.1 Gravitational Waves 963 13.2 LIGO 965 13.3 Limits to Measurement 965 14 Holographic Interferometry 965 14.1 Strain Analysis 965 14.2 Vibration Analysis 966 14.3 Contouring 966 15 Moir?e Techniques 967 15.1 Grating Interferometry 967 16 Speckle Interferometry 968 16.1 Electronic Speckle Pattern Interferometry (ESPI) 968 16.2 Phase-shifting Speckle Interferometry 968 16.3 Vibrating Objects 969 Glossary 969 References 970 Further Reading 973 ÁËÎÊ_× LASER COOLING AND TRAPPING OF NEUTRAL ATOMS 975 0 KEYWORDS: laser cooling; atom trapping; optical lattice; Bose–Einstein condensation. 1 Introduction 977 1.1 Temperature and Entropy 977 1.2 Phase Space Density 978 2 Optical Forces on Neutral Atoms 978 2.1 Radiative Optical Forces 979 2.2 Dipole Optical Forces 979 2.3 Density Matrix Description of Optical Forces 980 2.3.1 Introduction 980 2.3.2 Open Systems and the Dissipative Force 980 2.3.3 Solution of the OBEs in Steady State 981 2.3.4 Radiative and Dipole Forces 982 2.3.5 Force on Moving Atoms 982 3 Laser Cooling 982 3.1 Slowing Atomic Beams 982 3.2 Optical Molasses 984 3.2.1 Doppler Cooling 984 3.2.2 Doppler Cooling Limit 985 3.2.3 Atomic Beam Collimation – One-dimensional Optical Molasses – Beam Brightening 986 3.2.4 Experiments in Three-dimensional Optical Molasses 987 3.3 Cooling Below the Doppler Limit 988 3.3.1 Introduction 988 3.3.2 Linear ? Linear Polarization Gradient Cooling 988 3.3.3 Origin of the Damping Force 990 3.3.4 The Limits of Sisyphus Laser Cooling 991 4 Traps for Neutral Atoms 991 4.1 Dipole Force Optical Traps 992 4.1.1 Single-beam Optical Traps for Two-level Atoms 992 4.1.2 Blue-detuned Optical Traps 993 4.2 Magnetic Traps 994 4.2.1 Introduction 994 4.2.2 Magnetic Confinement 994 4.2.3 Classical Motion of Atoms in a Quadrupole Trap 996 4.2.4 Quantum Motion in a Trap 997 4.3 Magneto-optical Traps 997 4.3.1 Introduction 997 4.3.2 Cooling and Compressing Atoms in an MOT 999 4.3.3 Capturing Atoms in an MOT 999 4.3.4 Variations on the MOT Technique 1000 5 Optical Lattices 1000 5.1 Quantum States of Motion 1000 5.2 Properties of 3-D Lattices 1002 5.3 Spectroscopy in 3-D Lattices 1003 5.4 Quantum Transport in Optical Lattices 1004 6 Bose–Einstein Condensation 1005 6.1 Introduction 1005 6.2 Evaporative Cooling 1005 6.2.1 Simple Model 1006 6.2.2 Application of the Simple Model 1007 6.2.3 Speed of Evaporation 1008 6.2.4 Limiting Temperature 1008 6.3 Forced Evaporative Cooling 1009 7 Conclusion 1010 Glossary 1010 References 1012 ÁËÎÊ_× LASER ISOTOPE SEPARATION 1015 0 KEYWORDS * separation; isotope; photoionization; photodissociation; laser; multiphoton 1 Introduction 1016 2 Advantages of Laser Isotope Separation 1018 3 Photoionization Isotope Separation Method (AVLIS) 1019 4 Photodissociation Isotope Separation Techniques (MLIS) 1020 4.1 IR-UV Photodissociation 1020 4.2 Multiple-photon IR Photodissociation 1021 5 Development of Industrial LIS Technology 1023 5.1 The Scaling of the LIS Process 1023 5.2 The Scaling of the AVLIS Technology 1023 5.3 The Scaling of the MLIS Technology 1025 5.3.1 Separating Uranium Isotopes 1025 5.3.2 Carbon-isotope Separation 1025 6 Conclusion 1026 Glossary 1027 References 1027 Further Reading 1028 ÁËÎÊ_× LASER PHYSICS 1029 0 KEYWORDS * laser; coherent radiation; laser, solid-state; laser, gas; laser, semiconductor; laser * dynamics; rate-equation model; tunable lasers; mode-locked lasers; optical amplifiers; * frequency conversion. 1 Introduction 1030 2 Basic Theory of Operation 1031 2.1 Population Inversion and Stimulated Emission 1031 2.2 Pumping and Relaxation Processes 1031 2.3 Resonators and Cavity Modes 1033 3 Important Characteristics of Laser Radiation 1034 3.1 Linewidth – Spectral Brightness 1034 3.2 Intensity and Directionality (Angular Confinement) – Spatial Brightness 1034 3.3 Short Pulses – Temporal Brightness 1034 4 Types of Lasers 1035 4.1 Solid-state Lasers 1035 4.2 Gas Lasers 1037 4.3 Dye Lasers 1039 4.4 Semiconductor Lasers 1040 4.5 UV and X-ray Lasers 1044 4.6 Free-electron Lasers 1045 5 Laser Dynamics 1045 5.1 Rate-equation Model 1045 5.2 Buildup from Noise 1047 5.3 Threshold 1047 5.4 Gain Saturation 1047 5.5 Laser Efficiency 1048 5.6 Multimode Operation 1048 5.6.1 Spatial Hole Burning 1049 5.6.2 Spectral Hole Burning 1049 5.6.3 Single-frequency Operation 1050 6 Types of Pulsed Operation 1051 6.1 Long-pulse Operation 1051 6.1.1 Relaxation Oscillations 1051 6.2 Q-switched Operation 1052 6.3 Gain-switched Operation 1052 6.4 Cavity-dumped Operation 1053 6.5 Mode-locked Operation 1053 6.5.1 Active Mode Locking 1054 6.5.2 Passive Mode Locking 1054 7 Control of Laser Output 1055 7.1 Frequency Tuning 1055 7.2 Amplitude Modulation 1055 8 Oscillator–Amplifier Systems 1056 9 Issues in Laser Design 1056 10 Frequency Conversion and Nonlinear Control of Laser Radiation 1057 Glossary 1058 Further Reading 1062 ÁËÎÊ_× LASERS, DYE 1065 0 KEYWORDS * lasers; tunable; tunable lasers; dye lasers; solid-state dye lasers; multiple prism; * dispersion theory; femtosecond lasers. 1 Introduction 1066 2 Energy Levels and Rate Equations 1068 3 Laser-pumped Pulsed Dye Lasers 1070 4 Flashlamp-pumped Dye Lasers 1075 5 Continuous-wave Dye Lasers 1081 6 Femtosecond Dye Lasers 1084 7 Solid-state Dye Lasers 1086 8 Linewidth Narrowing and Intracavity Dispersion 1087 9 Applications 1089 Glossary 1092 References 1094 Further Reading 1096 ÁËÎÊ_× LASERS, EXTREME UV AND SOFT X-RAY 1097 0 KEYWORDS * neon-like; nickel-like; hydrogen-like; collisional excitation; recombination. 1 Introduction 1098 1.1 First Demonstrations of X-ray Lasers 1099 1.1.1 Neon-like Selenium Collisional Excitation Laser 1099 1.1.2 Hydrogen-like Carbon Recombination Laser 1099 2 Development of the Prepulse Technique 1100 2.1 Neon-like Collisional Excitation Lasers 1100 2.2 Nickel-like Collisional Excitation Lasers 1100 3 Tabletop Laser-driven X-ray Lasers 1101 3.1 Neon-like Titanium Laser 1102 3.2 Nickel-like Palladium Laser 1102 3.3 Longitudinally Pumped Lasers 1103 3.4 Gas Puff Targets 1104 4 Tabletop Capillary Discharge Lasers 1104 4.1 Neon-like Argon Capillary Discharge Laser 1104 5 Alternative X-ray Laser Schemes 1105 5.1 Optical Field Ionization 1105 5.1.1 Hydrogen-like Lithium Recombination Laser 1105 5.1.2 Palladium-like Xenon and Nickel-like Krypton Collisional Excitation Laser 1105 5.2 Resonant Photopumping Schemes 1105 5.3 Inner-shell Excitation 1105 5.4 X-ray Free Electron Laser 1106 6 Conclusion 1106 Acknowledgment 1107 Glossary 1107 References 1108 Further Reading 1110 ÁËÎÊ_× LASERS, FREE-ELECTRON 1111 0 KEYWORDS * free-electron laser; undulator; microbunching; SASE FEL; FEL oscillator; * FEL amplifier; FEL parameter; gain length. 1 Introduction 1112 2 Physical and Technical Principles 1115 2.1 Undulator Spontaneous Radiation 1116 2.2 The FEL Amplification 1117 2.3 The Small-signal Gain Regime 1120 2.4 High-gain Regime and Electron Beam Requirement 1121 2.5 Three-dimensional Effects 1123 2.6 Longitudinal Effects, Starting from Noise 1124 2.7 Storage Ring–based FEL Oscillators 1126 3 Present Status 1127 3.1 Single-pass Free-electron Lasers 1127 3.2 Free-electron Laser Oscillators 1128 4 Future Development 1130 Glossary 1131 References 1133 Further Reading 1134 ÁËÎÊ_× LASERS, GAS 1135 0 KEYWORDS: gas laser; pumping mechanisms; He–Ne laser; ion laser; excimer laser; CO2 laser; * laser application; material processing; laser medicine. 1 Introduction 1136 2 Principles of Operation 1137 3 Characteristics of Gas Lasers 1139 4 Laser Excitation Processes and Specific Gas Lasers 1141 4.1 Electron-impact Excitation 1141 4.1.1 Copper-vapor Laser 1142 4.1.2 Rare-gas Ion Lasers 1143 4.2 Excitation Transfer 1146 4.2.1 He–Ne Laser 1146 4.2.2 He–Cd Laser 1149 4.2.3 CO2 Laser 1150 4.3 Reactive Collisions: Excimer Lasers 1152 4.4 Chemical Lasers: HF, Coil 1157 4.5 Other Lasers in the Far-infrared, UV, and Soft X-ray Regions 1158 5 Applications 1158 5.1 Material Processing 1159 5.2 Marking and Laser Evaporation 1161 5.3 Microlithography 1162 5.4 Photochemical Processing 1163 5.5 Stereolithography 1165 5.6 Lasers in Medicine 1165 Glossary 1166 References 1167 Further Reading 1167 ÁËÎÊ_× LASERS, INDUSTRIAL USE OF 1169 0 KEYWORDS: laser-material processing; welding; cutting; drilling; surface treatment; cleaning; * bending; rapid prototyping. 1 Introduction 1171 2 Basic Principles 1171 2.1 Lasers and Beam Properties 1172 2.1.1 Primary Industrial Lasers 1172 2.1.2 Beam Properties 1174 2.2 Principles of Laser Processing 1175 2.2.1 Laser–material Interaction 1175 2.2.2 Processing Regimes 1176 2.2.3 Beam Optics and Delivery 1177 2.2.4 General Advantages and Limitations 1178 3 Major Applications 1179 3.1 Surface Treatment 1179 3.1.1 Transformation Hardening 1180 3.1.2 Surface Melting 1181 3.1.3 Alloying 1181 3.1.4 Cladding (Hardfacing) 1182 3.1.5 Other Surface Treatments 1182 3.1.6 Advantages and Limitations of Laser-surface Treatments 1183 3.2 Welding 1183 3.2.1 Process 1183 3.2.2 Applications 1186 3.3 Drilling (Piercing) 1188 3.3.1 Process 1188 3.3.2 Applications 1189 3.4 Cutting 1190 3.4.1 Process 1191 3.4.2 Applications 1194 3.5 Marking 1195 3.5.1 Process 1195 3.5.2 Applications 1196 4 Miscellaneous Applications 1197 4.1 Electronic Circuits 1197 4.1.1 Annealing 1197 4.1.2 Trimming 1197 4.1.3 Scribing 1198 4.1.4 Soldering 1198 4.1.5 Repairs 1198 4.1.6 Deposition 1199 4.1.7 Oxidation and Nitridation 1199 4.2 Prototype or Low-volume Manufacture 1199 4.3 Forming 1201 The Thermal Gradient Method (TGM) 1201 Buckling 1201 Upsetting 1201 4.4 Cleaning 1202 4.5 Other Processes 1203 Lasers, Industrial Use of 1171 4.5.1 Ablation 1203 4.5.2 Shock hardening 1203 4.5.3 Grain Refining 1204 4.5.4 Curing 1204 4.5.5 3D Laser Machining 1204 4.5.6 Laser-assisted Machining 1204 4.5.7 Laser Scabbling 1205 5 New Developments 1205 6 Summary 1206 Glossary 1207 References 1208 Further Reading 1209 ÁËÎÊ_× LASERS, MEDICAL USE OF 1211 0 KEYWORDS: laser–tissue interaction; laser surgery; laser tissue welding; refractive surgery; * photoablation; photodynamic therapy (PDT); optical tweezer; laser scanning confocal microscopy; * optical tomography. 1 Introduction 1212 2 Physics of laser–tissue Interaction 1215 2.1 laser–tissue Interaction Regimes 1215 2.2 Tissue Physical Properties 1216 2.2.1 Tissue Optical Properties 1216 Transport Theory 1217 Diffusion Approximation 1219 2.2.2 Tissue Thermal Properties 1220 2.2.3 Tissue Structural Properties 1221 2.3 Nonablative Tissue Effects 1222 2.4 Laser Tissue Ablation 1222 2.5 Nonlinear laser–tissue Interactions 1224 2.6 Laser Micromanipulation 1225 2.6.1 Optical Tweezer 1225 2.6.2 Laser Microdissection 1227 2.7 Sub-diffraction-limit Microscopy and Ablation 1227 2.8 Multi Photon Microscopy 1228 3 Therapeutic Applications 1228 3.1 Ophthalmology 1228 3.2 Surgery 1231 3.2.1 Urology 1231 3.2.2 Gynecology 1232 3.2.3 Otolaryngology 1232 3.3 Dermatology 1232 3.4 Cardiology 1234 3.5 Orthopedics 1235 3.6 Dentistry 1235 3.7 Photodynamic Therapy (PDT) 1235 3.8 Biostimulation 1237 3.9 Laser Tissue Welding 1238 3.10 Laser Energy-delivery Systems 1238 3.11 Surgical Laser Safety 1239 4 Diagnostic Applications 1239 4.1 Laser-based Optical Imaging in Medicine and Biology 1239 4.1.1 Laser Scanning Confocal Microscopy 1239 4.1.2 Laser Imaging for Ophthalmic Diagnosis 1240 4.1.3 Optical Tomography 1241 4.2 Spectroscopic Monitoring and Diagnosis 1244 4.3 Laser-based Biomedical Instrumentation 1247 5 Conclusion 1248 References 1249 Further Reading 1250 ÁËÎÊ_× LASERS, SEMICONDUCTOR 1251 0 KEYWORDS * semiconductor laser; laser diode; photonics; compact light source; heterostructure; * fiber-optic telecommunications; optical disk. 1 Introduction 1252 2 History 1253 3 Structures, Materials, and Operation Principles 1254 3.1 Double Heterostructure 1254 3.2 Fabry–P?erot Cavity 1257 3.3 Lasing Threshold Condition 1257 3.4 Stripe Geometry 1258 3.5 Materials and Emission Wavelengths 1259 3.5.1 III–V Compounds 1259 3.5.2 IV–VI Compounds 1260 3.5.3 II–VI Compounds 1260 4 Fundamental Characteristics 1260 4.1 Light–Current Characteristics 1260 4.2 Beam Profile and Polarization 1262 4.3 Spectral Characteristics 1263 4.4 Dynamic Characteristics 1265 5 New Structures and Functions 1267 5.1 Quantum-well Lasers 1267 5.2 Distributed-feedback and Distributed Bragg-reflector Lasers 1268 5.3 Semiconductor-laser Arrays 1269 5.4 Surface-emitting Lasers 1270 6 Summary 1270 Glossary 1271 References 1272 Further Reading 1273 ÁËÎÊ_× LASERS, SOLID-STATE 1275 0 KEYWORDS * solid-state lasers; fiber lasers; rare-earth-doped materials; transition-metal-doped materials. 1 Introduction 1276 2 History 1277 3 Properties of Gain Media and Pump Sources 1278 3.1 Gain Media 1279 3.1.1 Gain Media Doped with Rare-earth Ions 1279 Nd * YAG and Other Nd-doped Materials 1281 Er-doped Glass 1284 Yb-doped Materials 1285 Other Rare-earth-ion-doped Lasers 1285 3.1.2 Gain Media Doped with Transition-metal Ions 1286 Ruby, Alexandrite, andOther Cr3+-doped Materials 1287 Ti :Al2O3 Lasers 1288 Other Transition-metal-ion-doped Materials 1289 3.2 Pump Sources 1290 3.2.1 Lamps 1290 3.2.2 Laser Sources 1291 4 Laser Design 1291 4.1 Gain-element Geometries 1292 4.1.1 Rods 1292 4.1.2 Zig-zag Slabs and Disks 1293 4.1.3 Optical Fiber 1294 4.2 Pump Geometries 1295 4.3 Laser Resonators 1295 5 Laser Manufacture 1296 5.1 Gain-element Fabrication 1296 5.2 Optical Requirements for Solid-state Lasers 1298 6 Applications of Solid-state Lasers 1299 6.1 Industrial Applications 1299 6.2 Military Applications 1299 6.3 Medical Applications 1300 6.4 Communications Applications 1301 6.5 Scientific Applications 1301 7 Summary 1302 Acknowledgment 1302 Glossary 1302 References 1302 Further Reading 1303 ÁËÎÊ_× LIDAR (LASER RADAR) 1305 0 KEYWORDS * lidar; laser–radar; laser; atmospheric optics; Rayleigh; aerosol; DIAL; Raman 1 Introduction 1306 2 Historical Overview 1306 3 LidarBasics 1307 3.1 Transmitter 1308 3.2 Receiver 1309 3.3 Signal Detection and Recording 1310 3.3.1 Photon Counting 1310 3.3.2 Analog Detection 1311 3.4 An Example of a Lidar Detection System 1311 4 Rayleigh Lidar 1312 5 Aerosol Lidar 1313 6 Doppler Effects and Wind Lidar 1314 6.1 Coherent Doppler Lidar 1315 7 Differential Absorption Lidar (DIAL) 1315 8 Raman Lidar 1316 9 Resonance Lidar 1317 10 Future 1318 Glossary 1319 References 1320 Further Reading 1321 ÁËÎÊ_× LIGHT AND LIGHTING SYSTEMS 1323 0 KEYWORDS * photometry; spectral sensitivity; lamps; luminaires; visual performance; efficiency; * luminous efficacy. 1 Definition of Light 1324 1.1 Luminous Efficiency Functions 1324 1.2 Terminology 1325 2 Lighting Equipment 1325 2.1 Lamps 1325 2.2 Luminaires 1327 2.3 Controls 1328 3 Lighting Concepts 1329 3.1 Visual Performance 1329 3.2 Brightness Perception 1330 3.3 Mesopic Vision 1331 3.4 Application Efficacy 1332 4 Discussion 1333 Acknowledgment 1334 Glossary 1334 References 1336 Further Reading 1336 ÁËÎÊ_× LINEAR OPTICS 1337 0 KEYWORDS: optics; refraction; diffraction; reflection; geometric optics; interference; polarization; * light. 1 Introduction 1339 2 Fundamental Properties of Light 1340 2.1 The Velocity of Light 1340 2.2 Dispersion 1341 2.3 The Doppler Effect 1341 2.4 Polarization 1342 2.5 Linear and Angular Momentum of Light Waves 1343 2.5.1 Linear Momentum of Electromagnetic Waves 1343 2.5.2 Angular Momentum of Electromagnetic Waves 1343 3 Optics of Plane Interfaces and Isotropic Media 1343 3.1 Reflection 1343 3.2 Refraction 1344 3.3 Transmission 1344 3.4 Total Internal Reflection 1345 3.5 Absorption 1346 3.6 Extinction 1346 4 Geometrical Optics 1346 4.1 Plane Mirrors 1347 4.2 Spherical Mirrors 1347 4.2.1 Concave Mirrors 1347 4.2.2 Convex Mirrors 1348 4.3 Spherical Lenses 1349 4.3.1 Single-interface Lens 1349 4.3.2 Double-interface Lens; Thin Lens 1350 4.4 Thick Lenses 1350 4.5 Matrix Optics 1351 4.6 Simple Systems 1351 4.6.1 The Eye 1351 4.6.2 The Magnifying Glass or Simple Microscope 1352 4.6.3 The Compound Microscope 1353 4.6.4 The Telescope 1353 The Astronomical Telescope 1353 The Terrestrial Telescope 1354 5 Interference Phenomena 1354 5.1 Interference 1354 5.1.1 Two-beam Interference 1355 Newton’s Rings and Fizeau Fringes 1356 Antireflection Coating 1357 The Michelson Interferometer 1358 5.1.2 Multiple-beam Interference 1359 Diffraction Gratings 1359 The Fabry-P?erot Interferometer 1360 5.2 Diffraction 1361 5.2.1 Fresnel Diffraction 1361 Rectangular Aperture 1362 Half-plane Obstruction 1363 Arago’s Bright Spot 1363 5.2.2 Fraunhofer Diffraction 1363 Linear Slit, Rectangular Aperture 1364 Circular Aperture 1364 Annular Aperture 1365 5.2.3 Fundamental Consequences of Diffraction 1365 5.3 Thin-film Optics 1366 5.4 Holography 1366 5.5 Fourier Optics 1367 6 Anisotropic Media 1367 6.1 Linear Birefringence 1368 6.1.1 Crystal Polarizers 1369 6.1.2 Retardation Plates 1369 Quarter-wave Plate 1370 Half-wave Plate 1370 6.1.3 Compensators 1371 6.2 Circular Birefringence 1371 6.3 Electro-optical Effects 1372 6.3.1 The Kerr Effect 1372 6.3.2 The Pockels Effect 1372 6.4 Magneto-optical Effect, Faraday Effect 1373 6.5 Acousto-optical Effects 1374 7 Recent Developments 1374 7.1 Fiber Optics and Light Guides 1374 7.2 Integrated Optics 1375 7.3 Diffractive Optics 1376 7.3.1 Optical-imaging System Correction 1376 7.3.2 Unconventional Applications 1376 7.3.3 Binary Optics 1377 7.4 Point Spread Function Engineering 1377 7.5 EUV- and X-Ray Optics 1377 7.6 Adaptive Optics 1378 8 Conclusions 1378 Glossary 1378 References 1380 Further Reading 1380 ÁËÎÊ_× LUMINESCENCE 1383 0 KEYWORDS: luminescence; photoluminescence; cathodoluminescence; thermoluminescence; * chemiluminescence; sonoluminescence; electroluminescence. 1 Introduction 1384 2 Photoluminescence (PL) 1385 2.1 Instrumentations 1387 2.2 Photoluminescence Kinetics and Excitation Spectra 1388 2.3 Time Resolution 1388 2.4 Spatial Resolution 1389 2.5 External Perturbations 1390 3 Cathodoluminescence (CL) 1390 3.1 CL Generation Mechanism 1391 3.2 Instrumentations 1392 3.3 Comparing PL and CL 1394 4 Thermoluminescence (TL) 1394 4.1 Excitations and Defects 1395 4.2 Thermal Excitations and Recombinations 1395 4.3 Analysis of TL Spectra 1396 4.4 Instrumentations 1399 4.5 Applications 1400 5 Chemiluminescence (ChL) 1400 5.1 Excitations and Emissions 1401 5.2 Chemical Reactions 1402 5.3 Gas Phases 1402 5.4 Liquid Solutions 1403 5.5 Instrumentations 1404 5.6 Applications 1406 6 Sonoluminescence (SL) 1407 6.1 Instrumentations 1409 6.2 Bubble Dynamics and Light Emission 1409 7 Electroluminescence (EL) 1413 7.1 EL Device Structures and EL Emission Mechanisms 1414 8 Summary 1417 Glossary 1418 References 1419 Further Reading 1421 ÁËÎÊ_Ò V O L. III Magneto-optical Devices - Optical Metrology ÁËÎÊ_× MAGNETO-OPTICAL DEVICES 1423 0 KEYWORDS: magneto-optical effect; Faraday effect; Kerr effects; birefringence; cotton–mutton effect; * magneto-optic modulator; magneto-optical sensor; magneto-optic memories; * hybrid recording. 1 Introduction 1425 2 History and Types of Magneto-optical Effects 1425 3 Physical Origins of the Magneto-optical Effects 1426 4 Magneto-optical Effects 1428 4.1 Magnetic Circular Birefringence and Dichroism – Faraday Rotation and Ellipticity 1428 4.2 Magnetic Linear Birefringence – Voigt and Cotton–Mouton Effects 1431 4.3 Kerr Effect 1432 4.4 Microscopic Description 1434 4.5 Magneto-optical Effects in Integrated Optics 1435 Mode conversion and phase matching 1436 4.6 New Magneto-optical Effects 1437 5 Magneto-optic Materials 1437 5.1 Transmission Materials 1437 5.2 Reflection Materials 1438 6 Applications and Devices 1439 6.1 Nonreciprocal Devices 1439 6.1.1 Isolator 1439 6.1.2 Circulator 1440 6.2 Magneto-optic Modulator 1442 6.3 Deflector 1443 6.4 Magnetic-domain Imaging 1444 6.5 Magneto-optical Sensors 1444 6.5.1 Magnetic Field–imaging Devices 1444 Inhomogeneous Magnetic Field Imaging 1444 Magneto-optic Eddy-current Imager (MOI) 1444 Flux-penetration Imaging in High-Tc Superconductors 1445 Magneto-optic Readout Heads 1445 6.5.2 Field Sensors 1447 Current Sensors 1447 Magnetometers 1449 6.6 Magneto-optic Memories 1449 6.6.1 Beam-addressable Storage Devices 1449 6.6.2 Magneto-optical Disk 1451 6.7 Magneto-optic Displays and Printing Devices 1459 6.8 Optical–magnetostatic-wave Interactions 1463 6.9 Other Applications 1464 Glossary 1465 References 1466 Further Reading 1467 ÁËÎÊ_× MICROSCOPY 1469 0 KEYWORDS: optical microscopy; electron microscopy; field ion microscopy; acoustic microscopy; * scanning probe microscopy. 1 Introduction 1471 2 Optical Microscopy 1471 2.1 Image Formation 1472 2.1.1 Geometrical Image Formation 1472 2.1.2 Wave Optical Image Formation 1473 Coherent Illumination 1474 Koehler’s Illumination 1474 Useful Magnification 1475 Three-dimensional Image Formation 1476 2.2 Methods of Light Microscopy 1477 2.2.1 Phase Contrast Microscopy 1477 2.2.2 Interference Microscopy 1478 Mireau Interferometer Objective 1479 Differential Interference Contrast (Nomarsky DIC) 1480 Optical Coherence Microscopy 1480 2.2.3 Polarization Microscopy 1483 2.2.4 Fluorescence Microscopy 1484 2.2.5 Dark-field Microscopy 1484 2.2.6 Stereo Microscopy 1484 2.2.7 Laser-scanning Microscopy 1486 Confocal Microscopy 1487 Direct View Confocal Microscopy 1488 Two-photon Microscopy 1488 Raman Microscopy 1489 Fluorescence Correlation Spectroscopy (FCS) 1490 2.2.8 UV-, IR-, X-ray and Acoustical Microscopy 1490 Ultraviolet Microscopy 1490 Infrared Microscopy 1491 X-ray Microscopy 1492 Scanning Acoustical Microscopy 1493 3 Electron Microscopy 1494 3.1 Principles of Electron Optics 1494 3.1.1 Electron Sources 1495 3.1.2 Electron Lenses 1497 Lens Aberrations 1498 Correction of Aberrations 1499 3.2 Scanning Electron Microscope (SEM) 1499 3.2.1 Image Formation in Scanning Electron Microscopes 1499 3.2.2 X-ray Microanalysis 1501 3.2.3 Low-voltage SEM 1502 3.2.4 Environmental SEM (ESEM) 1504 3.3 Transmission Electron Microscope (TEM) 1504 3.3.1 Image Formation in Transmission Electron Microscopes 1504 3.3.2 Image Contrast Mechanisms in TEM 1508 3.3.3 Energy-filtering Transmission Microscope (EFTEM) 1509 3.4 Field Ion Microscopy 1513 4 Scanning Probe Microscopy 1515 4.1 Scanning Tunneling Microscopy 1515 4.1.1 STM Components 1516 4.1.2 Principles of Imaging and Spectroscopy 1517 4.1.3 Tunneling Spectroscopy 1519 4.2 Atomic Force Microscopy (AFM) 1520 4.2.1 Image Formation of AFM 1520 4.2.2 Modes of Operation 1522 Pulsed Force Mode 1522 Tapping Mode 1524 Microscopy 1471 Lateral Force Microscopy (LFM) 1524 Magnetic Force Microscopy 1524 Scanning Thermal Conductance Microscopy 1525 Scanning Capacitance Probe Microscopy 1525 4.3 Scanning Near-field Optical Microscopy (SNOM) 1525 Glossary 1528 References 1529 Further Reading 1530 ÁËÎÊ_× MODULATORS AND DEMODULATORS, OPTICAL 1533 0 KEYWORDS: optical modulators; integrated optics; acousto optics; electro-optics; photodetectors 1 Introduction 1535 Some examples of the uses of modulated light beams 1536 2 Methods in the Modulation of Light Waves 1537 2.1 Intensity Modulation 1537 2.2 Pulse Modulation 1538 2.3 Polarization Modulation 1539 2.4 Amplitude Modulation 1539 2.5 Phase Modulation 1539 2.6 Frequency Modulation 1539 2.7 Wavelength Modulation 1540 2.8 Deflection Modulation 1540 2.9 Modulation of Incoherent Light 1540 2.10 Modulation of Laser Light 1541 3 Optical Modulation, Devices, and Materials 1541 3.1 Mechanical Modulation 1541 3.2 Electrical Modulation 1541 3.3 Electro-optic Crystals 1542 3.3.1 Electro-optical Phase Modulator 1543 3.3.2 Electro-optical Frequency Modulator 1545 3.3.3 Electro-optical Intensity Modulator 1545 3.3.4 Electro-optical Polarization Modulator 1546 3.4 Electro-absorption Modulator 1547 3.5 Liquid Crystals 1549 3.6 Acousto-optical Modulators 1551 3.7 Magneto-optical Modulators 1553 3.8 Integrated-optical Modulators 1553 4 Optical Modulator Performance and Examples 1557 4.1 Frequency Response of Modulation 1557 4.2 Efficiency of Modulation 1557 4.3 Multispectral Modulation 1558 4.4 Examples of Modulation of Lasers – Laser Diodes 1558 4.5 Modulation of Lasers – Intracavity 1558 5 Demodulation and Detection 1559 5.1 Demodulation and Detection of Intensity-modulated Light 1560 5.2 Demodulation and Detection of Polarization-modulated Light 1560 5.3 Demodulation and Detection of Deflection-modulated Light 1560 5.4 Demodulation and Detection of Wavelength-modulated Light 1560 5.5 Interferometric Demodulation and Detection (Coherent Communications) 1560 5.6 Demodulation and Detection of Optical Subcarrier Modulation 1561 5.7 Laser Light Detection 1562 Glossary 1564 Further Reading 1565 ÁËÎÊ_× MONOCHROMATORS 1567 0 KEYWORDS * prism monochromators; Fabry–Perot etalons; plane-, spherical- and toroidal-grating monochromators; * crystal monochromators; birefringent filters; temporal pulse stretcher. 1 Introduction 1568 2 General Concepts 1568 3 Prism Monochromators 1570 4 Fabry–Perot Type Monochromators 1571 4.1 The Fabry–Perot Etalon as a Monochromator 1572 4.2 Interference Filters 1573 5 Grating Monochromators 1573 5.1 General Properties of Gratings 1574 5.2 Grating Monochromators for Visible and Infrared Radiation 1575 5.3 Grating Monochromators for Ultraviolet and Soft X rays 1576 5.3.1 Plane-grating Monochromators (PGMs) 1577 The SX-700 Parent Design 1577 5.3.2 Spherical-grating Monochromators (SGMs) 1577 The ‘‘Dragon’’ Parent Design 1579 5.3.3 Toroidal-grating Monochromators (TGMs) 1579 5.3.4 Variable Line-spacing Grating Monochromators 1580 6 Hard X-ray Monochromators 1580 6.1 Geometries for Crystal Monochromators 1581 6.1.2 The ‘‘Boomerang’’ Patent Design 1582 6.2 Curved Crystals 1582 7 Birefringent Filters 1583 8 The Monochromator as a Temporal Pulse Stretcher 1584 Glossary 1585 References 1588 Further Reading 1588 ÁËÎÊ_× MOTION PICTURE AND VIDEO LENSES 1591 0 KEYWORDS * camera lens factors; image aberrations; motion picture camera lenses; lens formats; * wide-screen lens systems; motion picture projection lenses; video camera lenses; video projector lenses; * video conference lenses; surveillance camera lenses. 1 Introduction 1592 2 State of the Art 1593 3 Camera Lenses 1594 4 Optical Factors 1594 5 Image Aberrations 1595 6 Light and Reflection 1598 7 Motion Picture Camera Lenses 1598 8 Specialty Lenses 1599 9 Lens Utilization 1601 10 Film-camera Formats 1602 11 Motion Picture Projection Lenses 1602 12 Theater Design Lens Requirement 1603 13 Wide-screen Technology 1606 14 Video Camera Lenses, Including Broadcast Television 1607 15 The Video Projector 1608 16 Video Conferencing Including Distance Learning 1610 17 Surveillance and Security Cameras 1610 19 Conclusion 1612 Acknowledgments 1613 Glossary 1613 Further Reading 1615 ÁËÎÊ_× NONLINEAR OPTICS 1617 0 KEYWORDS * nonlinear optics; nonlinear polarizabilities; nonlinear susceptibilities; optical Kerr * effect; second-harmonic generation; phase matching and quasi-matching; sum and * difference frequency generation; optical parametric amplification and oscillation; * electro-optics; third-order processes; optical bistability; optical phase conjugation; * self-induced transparency; self phase modulation; spatial and temporal solitons; * photonic gratings; self-focusing; self-transparency; coherent trapping; nonlinear optical * balance; acousto-optics; nonlinear magneto-optics; stimulated nonlinear processes; * stimulated light scattering; nonlinear optical materials and devices; photonic * structures; nonlinear optical spectroscopy (frequency and time resolved); single cycle * and extreme nonlinear optics. 1 Introduction 1619 2 Nonlinear Propagation 1623 2.1 Basic Nonlinear Propagation Equation 1623 2.2 Second-order Processes 1626 2.2.1 Conservation Laws 1627 2.2.2 Second-harmonic Generation (SHG) 1627 2.2.3 Phase Matching 1629 Refractive index dispersion compensation 1630 Wave vector mismatch compensation (quasiphase matching) 1630 2.2.4 Second-harmonic Generation in Reflection. Surface Nonlinear Diagnostics 1631 2.2.5 Sum- and Difference-frequency Generation and Parametric Amplification 1631 2.3 Third-order Processes 1633 2.3.1 Degenerate Four-wave Interactions; Nonlinear Grating Effects 1635 Optical Phase Conjugation 1636 Optical Bistability 1638 2.3.2 Light Self-action; Nonlinear Lensing Effects 1641 Self-focusing, Self-defocusing 1641 Light Self-trapping. Spatial Solitons 1642 White Self-transparency 1643 Self-phase Modulation 1644 Temporal Solitons. Modulational Instability 1644 2.4 Parametric Processes 1647 2.4.1 Electro-optics 1647 2.4.2 Magneto-optics 1648 2.4.3 Acousto-optics 1650 2.4.4 Nonlinear X-ray Optics 1651 3 Nonlinear Polarization 1652 3.1 Macroscopic Aspects. Susceptibilities 1652 3.2 Microscopic Description. Polarizabilities 1654 3.2.1 Local Approximation 1654 3.2.2 Microscopic Polarizabilities 1656 3.2.3 Local Field Corrections 1658 3.2.4 Macroscopic Polarizabilities. Susceptibilities 1659 3.2.5 Cascading Processes 1659 3.2.6 Nonlocal Effects. Molecular Chirality 1659 3.3 Nonresonant Regime. Electronic Nonlinearities 1660 3.3.1 Second-order Polarizabilities 1661 3.3.2 Third-order Polarizabilities 1662 3.4 Resonant Regime. Stimulated Nonlinear Processes 1663 3.4.1 Two-photon Resonances 1664 3.4.2 Stimulated Raman Scattering 1666 3.4.3 Stimulated Brillouin and Rayleigh Scattering 1668 3.4.4 Optical Balance 1669 3.5 Nonlinear Effects in Two- and Three-level Systems 1670 3.5.1 Two-level Systems 1670 Bloch Equations. Dressed Atom States 1671 Nonlinear Optics 1619 Nonlinear Response 1672 Self-induced Transparency 1673 3.5.2 Three-level Systems. Coherent Trapping 1674 3.6 Extreme Nonlinear Optics. The Single Cycle Regime 1675 4 Nonlinear Optical Materials and Devices 1676 4.1 Nonlinear Optical Materials 1676 4.1.1 Materials for Second-order Effects 1677 4.1.2 Materials for Third-order Effects 1679 4.1.3 Photonic Materials. Confinement 1681 4.2 Nonlinear Optical Devices 1682 4.2.1 Quadratic Effect Devices. Quasiphase-matching. THz Generation 1683 4.2.2 Quatric (Cubic) Effect Devices 1683 5 Nonlinear Optical Spectroscopy and Diagnostics 1684 5.1 Nonlinear Optical Spectroscopy in the Frequency Domain 1684 5.1.1 Two-photon (Sum) Spectroscopy 1685 5.1.2 Saturation Spectroscopy 1686 5.1.3 Raman Spectroscopy 1687 5.2 Nonlinear Spectroscopy in the Time Domain 1688 5.2.1 Local Time-resolved Techniques 1689 5.2.2 Nonlocal Time-resolved Techniques 1691 5.3 Nonlinear Polarization-state Spectroscopy 1692 6 Conclusions and Trends 1692 Glossary 1695 References 1697 Further Reading 1699 ÁËÎÊ_× OPTICAL ABERRATIONS 1701 0 KEYWORDS * aberration; spherical aberration; coma; astigmatism; field curvature; distortion; * chromatic aberration. 1 Introduction 1702 1.1 Reference Sphere 1702 1.2 Ray Model 1702 1.3 Normalized Coordinates 1702 2 Form of Optical Aberrations 1703 2.1 Wave Front Aberration Polynomial 1703 2.2 Ray Aberrations 1703 3 Wave Front Aberration Expansion 1705 3.1 Zeroth-order Wave Front Aberrations 1705 3.2 Second-order Wave Front Aberrations 1705 3.3 Fourth-order Wave Front Aberrations 1706 3.3.1 Spherical Aberration W040P4 1706 3.3.2 Coma W131HP3 cos ? 1707 3.3.3 Astigmatism W222H2P2 cos2 ? 1708 3.3.4 Field Curvature W220H2P2 1709 3.3.5 Distortion W311H3P cos ? 1709 3.4 Chromatic Aberrations 1710 4 Zernike Polynomials 1710 5 Conclusions 1711 Glossary 1712 Further Reading 1713 ÁËÎÊ_× OPTICAL ALIGNMENT 1715 0 KEYWORDS * autocollimation; optical systems; optical alignment; misalignment errors; aberrations; * star test. OPTICAL AND LASER SCANNING TECHNOLOGY 0 KEYWORDS: optical scanning; laser scanning; architecture, scanning; resolution, scanned; rotational scanner; * vibrational scanner; nonmechanical scanner; error reduction, scanned. 1 Introduction 1731 2 Scanner Architecture and Optical Transfer 1734 2.1 Objective Scan (Translational) 1734 2.2 Preobjective Scan (Angular) 1734 2.3 Postobjective Scan (Angular) 1735 2.4 Objective Scan (Angular) 1735 2.5 Objective Optics 1735 2.5.1 On-axis Optics 1735 2.5.2 Flat-field Optics 1737 2.5.3 Telecentricity 1737 2.5.4 Double-pass and Beam Expansion 1739 2.6 Power Transfer from a Coherent Source 1740 2.7 Over-and-underillumination (Over-and-underfilling) 1742 2.8 Duty Cycle 1742 2.9 Image Rotation and Derotation 1742 2.9.1 Image Derotation Methods 1743 3 Scanner Devices and Techniques 1743 3.1 Rotating Mirror Scanners 1744 3.1.1 Monogons 1745 3.1.2 Polygons 1745 3.1.3 Design Considerations 1745 3.1.3.1 Scanner-lens Relationships 1747 3.2 Holographic Scanners 1747 3.2.1 General Characteristics 1747 3.2.2 Scanner Configurations 1750 3.2.2.1 Operation in the Bragg Regime 1751 3.3 Vibrational Scanners 1752 3.3.1 The Galvanometer 1753 3.3.2 The Resonant Scanner 1753 3.3.3 Suspension Systems 1754 3.3.4 Adaptations and Comparisons 1754 3.3.5 The Fast Steering Mirror 1755 3.4 Acousto-optic Scanners 1755 3.4.1 Fundamental Characteristics 1757 3.4.2 Deflection Techniques 1757 3.5 Electro-optic (Gradient) Scanners 1758 3.5.1 Implementation Methods 1759 3.5.2 Drive Power 1759 3.5.3 Special Considerations 1760 4 Scanned Resolution 1760 4.1 Resolution Criteria 1760 4.2 Aperture Shape Factor 1760 4.3 Scanned Resolution; The Resolution Invariant 1762 4.3.1 Augmented Resolution; the Displaced Deflector 1763 Optical and Laser Scanning Technology 1731 4.3.2 Radial Symmetry and Scan Magnification 1764 4.3.3 Augmented Resolution with Scan Magnification 1764 5 Scan Error Reduction 1765 5.1 Available Methods 1765 5.2 Passive Methods 1766 5.2.1 Anamorphic Error Control 1766 5.2.2 Double-reflection Error Control 1766 6 Agile Beam Steering 1769 6.1 Phased Array Development 1769 6.1.1 Resolution of Phased Arrays 1773 6.2 Decentered Microlens Arrays 1774 7 Summary 1777 Glossary 1779 References 1782 Further Reading 1784 ÁËÎÊ_× OPTICAL COATINGS 1785 0 KEYWORDS: optical coatings; thin films; layers; optical filters; antireflection; reflectors; beam splitters; combiners. 1 Introduction 1786 2 Materials 1786 2.1 Metals, Dielectrics, and Semiconductors 1786 2.2 Refractive Index and Characteristic Admittance 1787 3 Coating Design Principles 1787 3.1 Basic Principles 1787 3.2 Surface Properties 1788 3.3 Films on Surfaces 1788 3.3.1 Quarter waves and the Quarter-wave Rule 1788 3.3.2 Half-wave Layers 1789 4 Principles of Coatings 1789 4.1 Antireflection Coatings 1789 4.1.1 Single-layer Antireflection Coatings 1789 4.1.2 Reference Wavelength and g 1789 4.1.3 Multilayer Antireflection Coatings 1790 4.2 Reflecting Coatings 1792 4.3 All-dielectric Coatings 1792 4.3.1 Filters Based on Repeated Structures 1793 4.3.2 Narrowband Filters 1794 4.3.3 Suppression of Unwanted Transmission 1795 4.4 Angle of Incidence Effects 1795 4.5 Metal Layers in Coatings 1796 4.5.1 Reflectors 1796 4.5.2 Transmitting Coatings 1797 4.5.3 Decorative Interference Coatings 1799 4.6 Coatings for Short Pulses 1800 4.6.1 Dispersion Correctors 1801 4.7 Rugate Filters 1802 5 Manufacturing Topics 1803 6 Accurate Calculations 1810 Acknowledgment 1811 Glossary 1811 Further Reading 1812 ÁËÎÊ_× OPTICAL COMMUNICATIONS 1813 0 KEYWORDS: photonics; lasers; optical fibers; optical-fiber communications; light-wave telecom; * broadband transmission; information transport. 1 Introduction 1814 2 OpticalFibers 1817 2.1 Fiber Loss 1818 2.2 Chromatic Dispersion 1819 2.3 Dispersion Limits 1820 3 Optical Amplifiers 1822 3.1 Amplifier Gain 1823 3.2 Gain Saturation 1824 3.3 Amplifier Noise 1824 4 Optical Transmitters 1826 4.1 L–I Laser Characteristics 1826 4.2 The InGaAsP Material 1827 4.3 Laser Output Spectrum 1828 4.4 Laser Chirp 1830 4.5 Laser Linewidth 1830 5 Light-wave Receivers 1831 5.1 Quantum Limit, Poisson Distribution 1832 5.2 Photodiodes 1833 5.3 Receiver Noise and Sensitivity 1834 5.4 Optical Preamplifiers 1835 5.5 Comparison of Receiver Sensitivities 1835 6 Modulation Formats 1836 6.1 RZ and NRZ 1836 6.2 TDM and WDM 1837 6.3 Subcarrier Modulation 1837 7 Optical Nonlinearities in Fibers 1837 7.1 Stimulated Brillouin Scattering (SBS) 1839 7.2 Stimulated Raman Scattering (SRS) 1840 7.3 Self-phase Modulation (SPM) 1841 7.4 Cross-phase Modulation (XPM) 1842 7.5 Four-wave Mixing (FWM) 1842 7.6 Solitons in Fibers 1843 8 Undersea Fiber Systems 1844 8.1 Undersea Fiber Cables 1845 8.2 Undersea Repeaters 1846 9 Terrestrial Long-haul Systems 1846 10 Fiber in the Loop 1847 10.1 FITL Issues and Challenges 1848 10.2 FITL Architectures 1849 11 CATV Light-wave Systems 1850 11.1 AM–VSB Transmission 1850 11.2 Compressed Digital Video and QAM 1852 Acknowledgment 1853 Glossary 1853 References 1854 Further Reading 1856 ÁËÎÊ_× OPTICAL COMPONENTS AND SYSTEMS 1557 0 KEYWORDS: geometrical optics; technical optics; optical components; optical systems; optical bench system; * lenses; mirrors; prisms; polarizers; optical fibers. 1 Introduction 1858 2 OpticalComponents 1859 2.1 Transmissive Imaging Components 1859 2.1.1 Single Lenses 1861 Best-form Lenses 1861 2.1.2 Doublets 1862 2.2 Transmissive Plane Optics 1862 2.2.1 Filters 1862 2.2.2 Prisms 1863 2.3 Mirrors 1864 2.3.1 Plane Mirrors 1865 2.3.2 Curved Mirrors 1865 2.4 Crystal Optical Components 1865 2.4.1 Prism Polarizers 1866 2.4.2 Retardation Plates 1867 2.5 Optical Fibers 1868 2.5.1 Multimode Fibers 1869 2.5.2 Single-mode Fibers 1870 2.5.3 Image-transmitting Ordered Fiber Bundles 1870 3 Optical Bench Systems 1870 3.1 Optical Benches 1871 3.2 Optical Tables 1871 3.3 Structural Systems 1872 4 Selections of Optical Systems 1873 4.1 Objectives 1873 4.2 Microscopes 1874 4.3 Telescopes 1874 4.4 Beam Expanders 1875 4.5 Scanning Systems 1876 4.6 Telecentric Systems 1877 4.7 Projection Systems 1877 4.8 Autocollimator 1878 4.9 Optical-beam Delivery System for Material Processing 1878 4.10 Interferometers 1879 Glossary 1880 Further Reading 1881 ÁËÎÊ_× OPTICAL COMPUTING 1883 0 KEYWORDS: Fourier transformation; acoustooptics; neural network; spatiotemporal processing; * logic gate; computing paradigm; optical computer; VLSI photonics. 1 Introduction 1884 2 Concept of Optical Computing 1886 2.1 Definition 1886 2.2 Motivation 1887 2.3 Advantages 1888 Parallelism 1888 High Speed 1888 Large Time- and Space-bandwidth Products 1888 Noninteraction in Free-space Propagation 1888 High Impedance and Noise Resistance Interconnection 1888 High Speed Interaction via Material 1888 2.4 Targets 1888 2.5 Classifications 1889 2.5.1 Data Representation 1889 2.5.2 Computing Schemes 1890 2.5.3 SIMD and MIMD 1890 3 Analog Optical Computing 1891 3.1 Fourier Image Processing 1891 3.2 Acoustooptical Signal Processing 1892 3.3 Optical Neural Computing 1893 3.4 Spatiotemporal Information Processing 1894 4 Digital Optical Computing 1895 4.1 Logic Gates and Circuits Construction 1895 4.2 Computing Paradigms 1895 4.3 Optical Computer Architectures 1897 4.4 VLSI Photonics 1898 5 Potential Applications of Optical Computing 1899 6 Conclusions 1900 Glossary 1900 References 1901 Further Reading 1902 ÁËÎÊ_× OPTICAL DESIGN 1903 0 KEYWORDS: * optical design; lens design; optical engineering; image formation; geometrical optics; aberrations. 1 Introduction 1904 2 Background for Optical Design 1905 2.1 General Remarks 1905 2.2 Geometrical Optics 1906 2.2.1 Paraxial Optics 1906 2.2.2 Gaussian Optics 1907 2.2.3 Image Irradiance 1908 2.2.4 The Significance of the Lagrange Invariant 1909 2.2.5 Marginal and Pupil Rays 1909 2.2.6 Basic Lens Types 1910 2.2.7 Finite (Exact) Raytracing 1912 2.2.8 Special Optical Elements 1913 2.3 Aberrations 1913 2.3.1 The Seidel Aberrations 1913 2.3.2 Aberrations of Thin Lenses and Mirrors 1914 2.3.3 Some Rules for the Correction of Aberrations 1916 2.3.4 Aberration Tolerances 1918 2.4 Image Formation 1919 2.4.1 Geometrical Image Formation 1919 2.4.2 Diffraction Theory of Image Formation 1920 2.5 Electro-optics 1924 3 The Process of Optical Design 1924 3.1 Specification 1925 3.2 Special Components 1925 3.3 First-order Layout 1926 3.4 A Refined First Solution 1928 3.5 Optimization 1929 3.6 Tolerancing and Manufacturability 1932 3.7 Stray Light 1934 3.8 Production and Test 1935 3.9 Optical but Not Lens Design 1935 4 Resources for Optical Design 1936 4.1 Software 1936 4.2 Databases, Books, and Other Resources 1938 5 Concluding Remarks 1939 Acknowledgment 1939 Glossary 1939 References 1941 Further Reading 1943 ÁËÎÊ_× OPTICAL FABRICATION 1945 0 KEYWORDS * optics; grinding; lapping; polishing; centering; coating; optical finishing; figuring; * injection molding; aspherical lenses. 1 Introduction 1946 2 Optical Materials 1948 2.1 Optical Glasses 1948 2.2 Polymers 1948 2.3 Metal Optics 1949 3 Fabrication of Glass Lenses in Large Quantity 1949 3.1 Generating 1949 3.2 Fine Grinding or Lapping 1950 3.3 Polishing 1951 3.4 Centering 1951 3.5 Coating 1952 3.6 Aspherical Glass-molding Process 1952 4 Injection Molding of Aspherical Plastic Lens 1953 4.1 Tooling 1953 4.2 Molding Process 1953 5 Single-point Diamond Turning and Ultraprecision Grinding Processes 1953 6 Precision Polishing Process 1955 6.1 Subaperture Tool Geometry 1956 6.2 Precession Polishing 1956 6.3 Magnetorheological Finishing 1956 6.4 Other Polishing Processes 1957 6.5 Optical Metrology 1957 Glossary 1957 References 1958 Further Reading 1959 ÁËÎÊ_× OPTICAL ILLUSIONS 1961 0 KEYWORDS * visual perception; color; motion; depth; lightness; brightness; simultaneous contrast; * perceptual constancy; adaptation; aftereffects; image ambiguity; perceptual reversals; * the Gelb effect; White’s illusion; Mach card; M?uller–Lyer illusion; Necker cube; * watercolor effect; Ames room; moon illusion; apparent motion; chromostereopsis; * Johansson figures. 1 Introduction 1962 Image ambiguity 1963 Adaptation and aftereffects 1964 Perceptual constancies 1964 2 Lightness, Brightness, and Color 1964 2.1 Lightness and Brightness 1965 2.1.1 Simultaneous Brightness Contrast 1965 Real world lightness illusions 1967 The Mach card 1968 Perceptual organization and simultaneous brightness contrast 1968 2.2 Color Perception 1970 2.2.1 Color Constancy 1970 2.2.2 Color Contrast 1971 Global contrast 1972 2.2.3 Chromatic Adaptation and Colored Afterimages 1973 2.2.4 Assimilation and Filling-in 1973 3 GeometryandForm 1975 3.1 Size Scaling 1975 The Ames room 1976 The moon illusion 1976 3.2 Ambiguous Figures and Perceptual Reversals 1977 4 Motion and Depth 1978 4.1 Apparent Motion 1978 4.1.1 Structure from Motion 1979 Biological motion 1980 4.2 Color and Depth 1980 Glossary 1982 References 1983 Further Reading 1984 ÁËÎÊ_× OPTICAL INSTRUMENTATION 1985 0 KEYWORDS * birefringence; blaze wavelength; chromatic aberration; color; comb generator; * cryogenic radiometers; ellipsometry; femtosecond laser; Fourier spectroscopy; * holography; laser gyro; optical frequency standard; optical radiation; refraction; * refractive index; refractometry; pinhole camera; polarimetry; polarization; soret plate; * spherical aberration; sugar scale; unit of length; unit of time; wavelength. 1 Introduction 1986 2 Character of Optical Radiation 1987 3 Phenomena and Applications 1990 3.1 Wavelength 1990 3.1.1 The Laser 1991 3.1.2 Interferometry 1992 3.1.3 Spectrometry 1997 3.1.4 Colorimetry 1998 3.2 Frequency 1999 3.2.1 Optical Frequency Standards 1999 3.3 Diffraction 2002 3.3.1 Gratings 2004 3.3.2 Imaging 2006 3.4 Refraction 2009 3.4.1 Refractometry 2010 3.4.2 Refractive Optics 2012 3.5 Polarization 2013 3.5.1 Polarimetry 2015 3.5.2 Ellipsometry 2016 3.6 Ultrashort Optical Pulses 2017 3.7 Discreteness of Photons 2018 3.7.1 Radiometry 2018 4 Conclusions 2019 Glossary 2019 References 2021 Further Reading 2023 ÁËÎÊ_× OPTICAL MATERIALS PHYSICS AND BASIC PROPERTIES 2025 0 KEYWORDS * refractive index; Maxwell’s equations; thin film; glass; ellipsometry; optical anisotropy; * polarization; reflection; transmission. 1 Introduction 2027 2 Physics of Optical Processes 2028 2.1 Definitions 2029 2.2 Classical Description of Light 2031 2.2.1 Maxwell’s Equations 2031 2.2.2 Boundary Conditions from Maxwell’s Equations 2033 2.2.3 Maxwell’s Equations and Light Waves 2033 2.2.4 Polarization 2034 2.3 Optical Functions 2035 2.3.1 Lorentz Oscillator Model 2036 2.3.2 Effective Medium Models 2038 2.3.3 Other Models of Dielectric Functions 2038 2.3.4 Causality and the Kramers–Kronig Relations 2039 2.3.5 Example * Optical Functions of Silicon and Silicon Dioxide 2040 2.3.6 Perturbations of Optical Functions: Strain and Temperature 2041 2.4 Light Reflection and Transmission at Interfaces 2042 2.5 Anisotropic Media 2043 2.5.1 Electric Field-induced Anisotropy 2046 2.5.2 Stress-induced Anisotropy 2048 3 Bulk Optical Materials 2049 3.1 Thermal, Mechanical, and Chemical Properties 2049 3.2 Glasses 2051 3.2.1 Types of Optical Glass 2052 Silica 2052 Optical Oxide Glasses 2052 Other Glasses 2053 Plastics 2053 3.2.2 Optical Properties of Glass 2053 3.3 Crystals 2055 3.3.1 Some Crystals Used in Optical Applications 2057 3.4 Liquids 2060 4 Thin Films 2062 4.1 Optical Reflection and Transmission with Thin Films 2062 4.1.1 Antireflection Coatings 2063 Example 1: Thin Films on SiO2 2064 Example 2: SiO2 on Silicon 2065 4.1.2 Filters 2067 4.1.3 Spectroscopic Reflectometry 2068 4.2 Ellipsometry 2069 4.2.1 Example: SiO2 on Silicon at a Single Wavelength 2070 4.2.2 Spectroscopic Ellipsometry 2071 Example 1: Thin-film SiO2 Grown on Silicon 2072 Example 2 * Silicon Nitride on Silicon 2074 Optical Materials 2027 4.3 Deposition of Thin Films 2076 Glossary 2081 Acknowledgments 2082 References 2083 Further Reading 2084 Physics of Optical Processes 2084 Bulk Optical Materials 2084 Thin Films 2084 ÁËÎÊ_× OPTICAL METROLOGY 2085 0 KEYWORDS * metrology; measurement; optics; optical testing; microscopy; interferometry. 1 Introduction 2086 2 Length Standards 2087 2.1 Optics and the Definition of the Meter 2087 2.2 Gage Block Interferometers 2088 3 Long and Short Distances 2089 3.1 Multiple-wavelength Laser Radar 2089 3.2 Fiber Sensors 2090 3.3 Chirp Laser Radar 2090 3.4 Large-scale Structures 2091 3.5 Narrow Gaps 2092 4 Stage Metrology 2092 4.1 Optical Encoders 2092 4.2 Multiaxis Laser Heterodyne Stage Metrology 2093 4.3 Heterodyne Laser Sources and Detectors 2095 4.4 Uncertainty Analysis 2096 4.5 Environmental Compensation 2096 5 Surface Form and Optical Testing 2097 5.1 Geometric Slope Testing 2097 5.2 Optical Flat and Laser Fizeau Interferometers 2098 5.3 Phase Estimation for Surface Profiling 2100 5.4 Advanced Techniques and Alternative Geometries 2101 5.5 Grazing Incidence 2102 5.6 Geometrically Desensitized Interferometry 2103 6 Object Shape and Geometric Dimensions 2103 6.1 Cylinders, Torics and Arbitrary Shapes 2103 6.2 Holographic Shape Recording 2104 6.3 Scanning Single-point Optical Probe 2105 6.4 Relational Measurements and Part Geometry 2105 6.5 Structured Light 2106 7 Microscopic Surface Form and Roughness 2107 7.1 Interference Microscopy 2107 7.2 Scanning White-light Interferometry 2108 7.3 Advanced Techniques and Geometries 2109 8 Lateral Metrology 2110 8.1 Micrometry 2110 8.2 Optical Comparators 2111 8.3 Laser Micrometers 2111 9 Conclusion 2111 Glossary 2112 References 2114 Further Reading 2117 ÁËÎÊ_Ò V O L. IV Optical Networks - Speckle and Speckle Metrology ÁËÎÊ_× OPTICAL NETWORKS 2119 0 KEYWORDS * optical fiber communication; photonic networks; high-capacity information * transmission integrated optics; optical access technology; broadband access. 1 Introduction 2120 2 High-capacity Transmission Systems 2120 3 OpticalNetworks 2126 4 Optical Access Networks 2130 References 2134 ÁËÎÊ_× OPTICAL RADIATION SOURCES AND STANDARDS 2137 0 KEYWORDS * luminous flux; incandescence; fluorescence; candela; luminous intensity; integrating sphere; * lamp; detector-based; blackbody; discharge tube; arc tube; optical sources; * optical standards. 1 Artificial Sources 2138 1.1 Blackbodies 2139 1.2 Incandescent Lamps 2139 1.3 Gas-discharge Lamps 2141 1.4 Additional Sources 2144 1.4.1 LEDs 2144 1.4.2 Lasers 2144 1.5 Other Sources of Light 2145 1.5.1 Radioactivity 2145 1.5.2 Chemiluminescence 2145 1.5.3 Electroluminescent Panels 2145 2 Optical Standards and Calibration 2146 2.1 Blackbody Cavity Theory 2146 2.1.1 Method of Gouff?e 2146 2.1.2 Blackbody Cavities 2146 2.2 Standards 2148 2.2.1 Background 2148 2.2.2 Luminous Flux 2149 2.2.3 Luminance Unit 2150 2.3 Calibration 2151 2.3.1 Luminous Intensity Calibration 2151 NIST luminous intensity standards calibration 2151 2.3.2 Luminous Flux Calibration 2151 NIST luminous flux standards and calibration 2151 2.4 Photometric Services 2152 Spectral irradiance lamps 2152 Spectral radiance lamps 2152 Special tests of radiometric sources 2152 Spectral radiance integrating sphere sources 2152 Spectroradiometric Detector Measurements 2152 UV silicon photodiodes 2152 Visible to near-infrared (NIR) silicon photodiodes 2153 2.5 International Standards 2153 3 Conclusion 2153 Glossary 2154 Acknowledgment 2154 References 2154 Further Reading 2155 ÁËÎÊ_× OPTICAL TECHNIQUES FOR MECHANICAL MEASUREMENT 2157 0 KEYWORDS * mechanical measurement; optical measurement; noncontact measurement; * holographic interferometry; electronic speckle pattern interferometry; optical * triangulation; laser Doppler velocimetry; laser Doppler anemometry; laser radar; * interferometry; moir?e; moir?e interferometry; displacement measurement; velocity * measurement; acceleration measurement; strain measurement; 3-D measurement; * vision systems 1 Introduction 2158 2 Gauging Systems/Presence Sensors 2158 3 Surface-finish Measurement 2159 4 Point Measurement 2161 4.1 Optical Triangulation 2161 4.2 Laser Radar 2162 4.3 Laser Interferometry 2163 4.4 Laser Doppler Velocimetry 2164 4.5 Laser Doppler Anemometry 2165 5 Measurement of Position and Displacement of an Area 2166 5.1 Electronic Speckle Pattern Interferometry 2167 5.2 Holographic Interferometry (HI) 2171 5.3 Moir?e Methods 2172 6 Measurement of Surface Form 2174 6.1 Laser Scanning 2175 6.2 Grid Projection 2175 6.3 HI and ESPI 2176 7 Vision Systems 2177 8 Conclusions 2179 Glossary 2179 References 2180 Further Reading 2180 ÁËÎÊ_× OPTICAL TECHNIQUES FOR THE ANALYSIS AND CHARACTERIZATION OF CHEMICALS AND MATERIALS 2183 0 KEYWORDS: spectroscopy; fluorescence; Raman; microscopy; imaging; nonlinear optics; harmonic * generation; chirality. 1 Introduction 2184 2 Fundamental Principles 2185 3 Infrared Spectroscopy 2187 4 Ultraviolet and Visible Absorption Spectroscopy 2189 5 Molecular Fluorescence 2191 6 Raman Spectroscopy 2193 7 Microscopy and Imaging 2195 8 Nonlinear Optical Methods 2197 9 Other Laser Methods 2199 10 Chiral Characterization Methods 2201 Acknowledgments 2202 Further Reading 2202 ÁËÎÊ_× OPTICAL TOMOGRAPHY 2203 0 KEYWORDS: near infrared; medical imaging; tomography; diffusion approximation; image * reconstruction; molecular imaging; photoacoustic imaging; optical * coherence tomography. 1 Introduction 2204 2 Basic Approaches to Optical Tomography 2206 2.1 Imaging Configurations 2206 2.2 Source and Detector Types 2208 2.3 System Example 1: Continuous-wave Functional Optical Topography System 2210 2.4 System Example 2: Time-domain Optical Tomography System 2211 3 The Physics of Optical Tomography 2214 3.1 Simple Modeling of Light Propagation in Tissue 2214 3.2 Advanced Modeling of Light Propagation in Tissue 2215 3.3 Optical Tomographic Image Reconstruction Using Models 2216 3.3.1 Differential (Linear) Imaging 2217 3.3.2 Absolute (Nonlinear) Imaging 2219 3.4 Multiwavelength OT: Extraction of Functional Information 2219 4 Advanced and Hybrid OT Techniques 2220 4.1 Dynamic Tomography 2220 4.2 Molecular Imaging 2222 4.3 Ultrasonic/OT Hybrid Techniques 2224 4.4 Optical Coherence Tomography 2224 Glossary 2229 Acknowledgments 2231 References 2231 Further Reading 2234 ÁËÎÊ_× OPTOELECTRONICS 2237 0 KEYWORDS * coherent and incoherent sources; lasers; waveguides; optical fibers; connectors; light * modulation; photodetectors; integrated optics; optoelectronic systems; optical communications. 1 Introduction 2238 2 Solid-state Emitters 2241 2.1 Light-emitting Diodes 2241 2.2 Semiconductor Laser Diodes 2244 2.2.1 Double-heterostructure Laser Diodes 2244 2.2.2 Quantum Well and Quantum Dot Lasers 2247 2.2.3 Single Frequency Lasers 2249 2.2.4 Vertical Cavity Surface Emitting Lasers (VCSELs) 2250 3 Optical Fibers as Waveguides 2251 3.1 Step-index Optical Fiber Fundamentals 2251 3.2 Dispersion in Optical Fibers 2255 3.3 Attenuation in Optical Fibers 2256 3.4 Cables 2258 3.5 Connectors and Splices 2259 4 Optical Amplifiers 2259 5 Modulators 2261 5.1 Electro-optic Modulators 2261 5.2 Acousto-optic Modulators 2264 5.3 Multiple Quantum Well Modulators 2265 6 Optical Switches, Multiplexers, and Isolators 2266 7 Photodetectors 2269 7.1 Fundamental Definitions and Characteristics 2269 7.2 pin Photodiode 2270 7.3 Avalanche Photodiode 2272 7.4 Heterojunction Avalanche Photodiodes 2273 8 Integrated Optics and Optoelectronics 2274 9 Optoelectronic Systems 2276 Glossary 2278 Acknowledgment 2283 Further Reading 2283 ÁËÎÊ_× PHOTOCHEMISTRY 2285 0 KEYWORDS * light absorption; continuous irradiation; flash photolysis; electronic transition; * charge-transfer; multiphoton processes; laser spectroscopy; photophysical processes 1 Introduction 2287 2 Photochemical Laws 2289 2.1 Light and Energy 2289 2.2 Light-absorption Principles 2289 2.3 Quantum Yields 2290 3 Fundamental Principles of Photophysics and Photochemistry 2291 3.1 Quantum Mechanical Principles of Absorption 2291 3.1.1 Linear Absorption 2292 3.1.2 Selection Rules 2292 3.1.3 Multiphoton Absorption 2294 3.1.4 Level Shifts 2295 3.1.5 Hole Burning 2296 3.1.6 Electronic Multiphoton Absorption 2296 3.1.7 Vibrational Multiphoton Absorption 2296 Vibrational-state Ladders 2296 Isolated Molecules 2297 Effects of Collisions 2297 3.2 Energy Partitioning and Dissipation Pathways 2298 3.2.1 Photophysical Pathways * Luminescence and Nonradiative Decay 2298 3.2.2 Randomization of Energy in Molecules 2300 3.2.3 Photochemical Pathways 2301 3.2.4 Energy Localization 2303 3.2.5 Ionization and Detachment 2304 3.2.6 Dissociation 2304 4 Types of Photochemical Experiments 2304 4.1 Continuous (cw) Photolysis 2304 4.1.1 Preparative Photochemistry 2304 4.1.2 Quantum-yield Determination and Product Identification 2305 4.2 Laser Flash Photolysis 2305 4.3 Ultrafast Intermediates 2308 4.4 Laser Spectroscopy 2310 4.5 Multiphoton Ionization (MPI) 2312 4.6 Multiphoton Dissociation (MPD) 2314 5 Photochemistry of Organic Compounds 2314 5.1 Electronic Transitions and Spectra of Organic Molecules 2314 5.2 Electronic Energy Transfer 2315 5.3 Reactions of Excited Species 2315 5.3.1 Reactivity of Excited Species 2315 5.3.2 Correlation Rules and Symmetry Conservations 2316 5.3.3 Intramolecular Processes 2316 Primary Dissociation Processes 2316 Photoisomerization 2318 Hydrogen Abstraction 2319 5.3.4 Intermolecular Processes 2320 Hydrogen Abstraction 2320 Addition Reactions 2320 Photochemistry 2287 6 Photochemistry of Inorganic and Coordination Compounds 2322 6.1 Spectra and Photochemistry 2323 6.1.1 Ligand-Field (LF) Transitions 2323 6.1.2 Ligand-to-metal (LMCT) and Metal-to-Ligand (MLCT) Charge-transfer Transitions 2324 6.1.3 Charge-transfer-to-solvent (CTTS) Transitions 2325 6.1.4 Other Charge-transfer Transitions 2326 7 Applications of Photochemistry 2326 7.1 Photography 2326 7.2 Holography 2327 7.3 Photopolymerization 2327 7.4 Surface Modification 2328 7.4.1 Etching 2328 7.4.2 Deposition 2329 7.5 Photoimaging 2329 7.6 Information Storage 2330 7.7 Photochromism 2330 7.8 Isotope Selection 2331 7.9 Chemical Analysis 2331 7.10 Biochemistry 2331 7.10.1 Photosynthesis 2332 7.10.2 Photochemistry of Vision 2333 7.10.3 Phototherapy 2334 7.11 Photochemical Treatment of Waters 2334 7.11.1 Homogeneous Photolysis and Photocatalysis 2334 7.11.2 Heterogeneous Photocatalysis 2335 8 Conclusion 2335 Acknowledgment 2335 Glossary 2336 References 2338 Further Reading 2341 ÁËÎÊ_× PHOTOEMISSION AND PHOTOELECTRON SPECTRA 2343 0 KEYWORDS * photoemission; photoelectron spectroscopy; electronic states; * valence electrons; core electrons; synchrotron radiation. 1 Introduction 2344 1.1 History 2344 1.2 Phenomena 2345 1.3 Theory 2348 2 Instrumentation 2349 2.1 Light Sources 2349 2.2 Detectors 2350 3 Photoelectric Yield and Absorption Spectroscopy 2352 3.1 Mechanism 2352 3.2 Unoccupied Atomic and Molecular Orbitals 2352 3.3 Solids 2353 3.4 Magnetic Dichroism 2353 3.5 Microspectroscopy 2354 4 Core-level Spectroscopy 2355 4.1 Origin of Core-level Shifts 2355 4.2 Atomic Case, Shakeup, and Shakeoff Satellites 2355 4.3 Adsorbates and Surfaces 2356 4.4 Bulk Solids 2359 5 Valence Spectroscopy 2360 5.1 Occupied Atomic and Molecular Orbitals 2360 5.2 Surface States 2361 5.3 Band Mapping 2362 5.4 Time-resolved, Pump-probe Measurements 2363 5.5 Inverse Photoemission 2363 6 Structural Methods 2364 6.1 EXAFS, SEXAFS, XSW, and PhD 2364 6.2 Photoelectron Diffraction 2365 7 Summary and Outlook 2366 Glossary * Definitions, Acronyms, Jargon 2367 Databases 2368 References 2368 ÁËÎÊ_× PHOTOGRAPHIC RECORDING 2371 0 KEYWORDS: digital images; silver halide; film; image chain; radiography; holography; silicon; arrays. 1 Introduction 2372 2 Principles of Photographic Recording 2374 2.1 Silver Halide Photography 2374 2.2 Silicon Array Photography 2380 2.3 Comparative Photographic Characteristics of Silver Halide and Silicon 2383 2.4 Color Reproduction 2384 2.5 Holographic Image Recording 2385 3 Imaging Materials from Silver Halides to Phosphors to Silicon 2386 3.1 Silver Halide Materials 2386 3.2 Silicon 2388 3.3 X-Rays and Radiography 2392 3.4 Infrared Image Detectors 2393 4 Applied Photographic Recording 2394 4.1 Clinical and Scientific Photography 2394 4.2 Holography 2395 Acknowledgment 2397 Glossary 2397 References 2398 Further Reading 2401 ÁËÎÊ_× PHOTOGRAPHY, DIGITAL 2403 0 KEYWORDS: digital photography; CCD image sensors; CMOS image sensors; digital halftones; * image enhancement; sampling artifacts; aliasing; color filter arrays; color image * interpolation; image system quality; micro-lenses; optical pre-filters; digital * photographic speed; image compression. 1 Introduction 2405 2 The Digital Imaging Chain 2405 3 Image Capture 2407 3.1 Camera Optics 2407 3.1.1 Camera Lenses 2407 3.1.2 Optical Prefilters 2412 3.1.3 Microlens Arrays 2414 3.2 Image Sensors 2414 3.2.1 Photodiodes 2415 3.2.2 MOS Capacitors 2416 3.2.3 Charge Readout Methods 2417 3.2.4 Charge-coupled Device Architectures 2419 3.2.5 Recent Advances in Imaging Sensor Technology 2421 3.2.6 Charge-transfer Efficiency 2422 3.3 Color-filter Arrays 2423 3.3.1 Additive and Subtractive Arrays 2424 3.3.2 Multiple-array Configurations 2426 3.4 Signal, Noise, and Speed 2426 4 Image Interpolation 2430 4.1 Whittaker–Shannon Interpolation 2430 4.2 Simple Interpolation by Convolution 2430 4.3 Logical Interpolation 2431 5 Sampling, Aliasing, and Artifacts 2432 5.1 Sampling and Aliasing 2432 5.2 Sampling in Color Systems 2435 5.3 Potential for Aliasing 2436 6 Image Compression and Storage 2437 6.1 JPEG Compression 2438 7 Image Processing and Manipulation 2440 7.1 Noise Reduction and Edge Enhancement 2441 7.2 Examples of Image Enhancement 2442 7.3 Image Manipulation and Protection 2443 8 Color Reproduction 2444 9 Digital Hard Copy 2447 9.1 Marking Engines 2447 9.2 Continuous-tone Printers 2447 9.3 Binary Printers 2448 10 Image Quality 2451 10.1 System Analysis for Sharpness 2451 10.2 System Analysis for Aliasing and Artifacts 2455 10.3 System Tradeoffs 2455 Glossary 2457 References 2459 Further Reading 2462 ÁËÎÊ_× PHOTOGRAPHY, PHYSICS AND TECHNOLOGY 2487 0 KEYWORDS: resolution; viewfinder; auto focus; film; digital detector; * photographic speed; SLR camera; bellows camera. 1 Introduction 2464 2 Formation of a Photographic Image 2465 2.1 Basic Parameters of Photographic Lenses 2465 2.2 Field of View 2466 2.3 Resolving Power in Photographic Images 2467 2.3.1 MTF of Photographic Lens 2468 2.3.2 MTF of Photographic Film 2468 2.3.3 MTF of Classical Digital Matrix 2468 2.3.4 Circle of Confusion 2471 2.4 Depth of Field 2471 2.5 Perspective 2473 2.6 Shifted and Tilted Image Generation 2473 3 Energy Balance in the Photographic Image 2474 3.1 Illuminance on the Detector 2475 3.2 Photographic Speed 2475 3.3 Flash Photography 2476 4 Technology of Modern Photographic Cameras 2477 4.1 Viewfinder Cameras 2477 4.2 Single-Lens Reflex Cameras (SLR) 2479 4.3 New Feature of Digital Still Photography 2481 4.4 Professional Bellows Camera 2482 5 Conclusion 2483 Acknowledgment 2483 Glossary 2483 References 2484 Further Reading 2485 ÁËÎÊ_× PHOTONICS 2487 0 KEYWORDS: photon; laser; diode laser; optical fibers; information technology; * optical communications; optical information storage; biophotonics 1 Introduction 2488 2 Light Sources in Photonics 2490 3 Control and Manipulation of Light 2494 4 OpticalFibers 2495 4.1 Photonic Crystal Fibers 2496 5 Information Technology, Optical Communications 2497 6 Optical Information Storage 2499 6.1 Displays 2501 7 Sensors and Precision Measurement 2501 8 Photonics Applications in Industry 2501 8.1 Photolithography 2502 9 Biophotonics, Biomedical Optics, Photomedicine 2502 9.1 Optical Coherence Tomography 2503 9.2 Optical Trapping, Manipulation, Tweezers, and Scissors 2505 10 Conclusion 2506 Glossary 2506 References 2507 Further Reading 2509 2511_× PHYSIOLOGICAL OPTICS 0 KEYWORDS: vision; eye; retina; brightness sensation; motion perception; * depth perception; pattern recognition; illusions 1 Introduction 2512 2 Biophysics of the Eye 2513 2.1 Optical System and Retinal Image 2513 2.2 Structure and Function of the Retina 2516 2.3 Eye Movements 2519 3 Neuronal Signal Processing 2520 3.1 Methods 2520 3.1.1 Electroretinogram (ERG) 2520 3.1.2 Visually Evoked Cortical Potentials (VECPs) 2520 3.1.3 Recordings from Microelectrodes 2521 3.1.4 Brain-Imaging Techniques 2521 3.2 The Structure of the Neuronal Visual System 2521 3.3 Receptive Fields and Spatial-frequency Channels 2523 4 Psychophysical Methods 2527 4.1 Threshold Definition and Measurement 2527 4.2 Suprathreshold Vision 2528 4.3 Data Acquisition and Evaluation 2529 5 Brightness Sensation 2531 5.1 Absolute Threshold 2531 5.2 Luminance Difference Threshold 2532 5.3 Detection of Spatial Luminance Structures 2533 6 Binocular Vision 2536 7 Temporal Signal Processing 2538 7.1 Temporal Resolution 2538 7.2 Motion Perception 2540 8 Color Vision 2541 9 Optical Illusions 2542 9.1 Illusory Contours 2542 9.2 3D Illusions 2543 9.3 Aftereffects 2543 10 Theories of Object Recognition 2544 Glossary 2546 References 2548 Further Reading 2550 ÁËÎÊ_× POLARIZATION OPTICS, POLARIMETERS AND POLARIZATION SPECTROMETERS 2551 0 KEYWORDS * polarization; polarimeter; saccharimeter; optical activity; optical rotation; chirality; * enantiomer; dichroism. 1 Introduction 2553 2 Polarization Optics 2554 2.1 Principles and Types of Polarizers 2554 2.2 Dichroism and Dichroic Foils 2554 2.3 Birefringence and Polarizing Prisms 2554 2.4 Brewster Reflection 2555 2.5 Thin-film Layer Polarizing Beam Splitters 2556 2.6 Scattering 2556 2.7 Phase Retarders 2556 3 Polarimetry 2557 3.1 History 2557 3.2 Biot’s Law and the Specific Rotation 2558 3.3 Rotatory Dispersion, Circular Dichroism, Temperature Dependence, and Mutarotation 2558 3.4 The International Sugar Scale (ISS) 2561 4 Polarimeters and Performances 2564 4.1 The Simple Circle Polarimeter 2564 4.2 Half-shadow Polarimeters 2564 4.3 Semiautomated Photoelectric Circle Polarimeters 2565 4.4 Automated Circle Polarimeters 2565 4.5 Quartz-wedge Compensation Polarimeters 2566 4.6 Magneto-optic Compensation 2567 4.7 Circular Dichroism Spectrometers 2567 4.8 Polarization Imaging and Polarization Analysis with Optical Fibers 2568 4.9 Applications and Analytical Performances 2568 4.10 Hyphenated Techniques Using Chiroptic Detectors 2569 4.11 Light Sources and Detectors 2570 5 Polarization Spectrometers 2571 5.1 Common Basics of Polarimetry and Polarization Spectrometry 2571 5.2 Analytical Coherent Forward Scattering Spectrometry 2574 5.2.1 Optical Linearization 2577 5.2.2 Multielement Analysis with Continuum Sources 2577 5.3 Nonlinear and Saturated Polarization Spectroscopy 2579 Glossary 2581 Acknowledgments 2583 References 2583 Further Reading 2585 ÁËÎÊ_× POLARIZED LIGHT, BASIC CONCEPTS OF 2587 0 KEYWORDS * polarization; birefringence; Jones vectors; Jones matrices; * Stokes parameters; Poincare sphere; optical rotary power. 1 Introduction 2588 2 States of Polarization Representations 2589 2.1 Jones Representation 2590 2.1.1 States of Linear Polarization 2590 2.1.2 States of Circular Polarization 2590 2.1.3 Elliptical States of Polarization 2591 2.2 Stokes Parameters 2591 2.3 Poincar?e Sphere 2592 2.4 The Stokes Vector 2593 3 Propagation in Birefringent Media 2594 3.1 Linear Optical Anisotropy of Materials 2594 3.1.1 Plane Wave in a Linear Anisotropic Medium 2595 3.1.2 Resolution of the Propagation Equations 2595 Notion of Birefringence 2596 3.1.3 Surface of the Indices 2596 Biaxial Media 2596 Uniaxial Media 2597 3.1.4 Eigenstates of Propagation 2598 3.1.5 Characteristics of a Plane Wave in a Linear Anisotropic Medium 2598 3.2 Circular Optical Anisotropy of Materials 2599 3.2.1 Effective Permittivity 2599 3.2.2 Plane Wave in a Pure Circular Anisotropic Medium 2599 3.2.3 Rotation of a State of Polarization 2599 4 Conclusion 2600 Glossary 2600 References 2601 Further Reading 2601 ÁËÎÊ_× RADIATION INTERACTION WITH MOLECULES 2603 0 KEYWORDS * molecular spectroscopy; microwave spectroscopy; infrared spectroscopy; * optical spectroscopy; Raman spectroscopy; Rydberg states; multiphoton spectroscopy; * second-harmonic generation; coherent anti-Stokes Raman scattering (CARS). 1 Introduction 2604 1.1 The Nature of Molecules 2604 1.2 Molecular Response to Electric Fields 2605 1.3 Molecular Response to Magnetic Fields 2606 2 First-order Effects 2606 2.1 Spectroscopy 2606 2.2 The Art and Science of Spectroscopy 2609 2.3 Microwave Spectroscopy 2611 2.4 Determination of Dipole Moments 2616 2.5 Hyperfine Structure 2616 2.6 Infrared Spectroscopy 2618 2.7 Raman Spectroscopy 2620 2.8 Optical Spectroscopy 2622 2.8.1 Intensities of Transitions 2625 2.8.2 Franck–Condon Principle 2625 2.8.3 Vibronic Interactions 2626 2.8.4 Rydberg States and Ionization Potentials 2628 2.9 Magnetic Resonance Spectroscopy 2628 3 Higher-order Effects 2629 3.1 The Hyper-Rayleigh and Hyper-Raman Effects 2630 3.2 Second-harmonic Generation 2630 3.3 Stimulated Raman Scattering 2631 3.4 The Inverse Raman Effect 2631 3.5 Coherent Anti-Stokes Raman Scattering (CARS) 2631 3.6 Raman-induced Kerr-effect Spectroscopy (RIKES) 2634 Glossary 2634 References 2635 Further Reading 2635 ÁËÎÊ_× REMOTE SENSING 2637 0 KEYWORDS * calibration accuracy; climate studies; earth studies; european space agency; * image interpretation; meteorology; NASA; radiometric imaging; satellite systems; * sensor data products; space studies; spectral imaging; space borne sensors. 1 Introduction 2638 2 Early History of Remote Sensing 2642 3 Basics of Remote Sensing 2642 3.1 Electromagnetic Radiation 2642 3.2 Atmosphere Transmission and Corrections 2643 3.3 Satellite Orbits 2648 3.4 Sensors 2649 3.5 Calibration and Characterization 2651 3.6 Data Products – The Results of Remote Sensing 2653 3.7 Visible to Shortwave Infrared 2653 3.8 Thermal Infrared 2658 3.9 Radar 2658 4 Examples of Remote Sensing Systems 2659 4.1 Landsat and SPOT 2660 4.2 EOS Terra and Aqua 2661 4.3 Envisat 2663 4.4 Commercial Sensors 2665 5 Future of Remote Sensing 2665 Glossary 2666 References 2667 Further Reading 2668 ÁËÎÊ_× SENSORS, OPTICAL 2669 0 KEYWORDS * optical sensors; light sources; photodetectors; optical elements; optical metrology 1 Introduction 2670 2 Light Sources 2671 2.1 Thermal Sources 2671 2.2 Line Sources 2673 2.3 Lasers 2674 3 Photodetectors 2679 3.1 Photomultipliers 2679 3.2 Photodiodes 2681 3.3 Other Detector Types 2682 3.4 Detector Noise 2684 4 Optical Elements 2684 4.1 Mirrors and Lenses 2684 4.2 Dispersive Elements: Prisms and Gratings 2685 4.3 Filters 2686 4.4 Optical Fibers 2686 4.5 Modulators 2688 5 ExamplesforOpticalSensors 2690 5.1 Measurement of Spatial Dimensions 2690 5.1.1 Incremental Encoders 2690 5.1.2 Optical Interferometry 2691 5.1.3 Optical Cross-correlation Sensors 2692 5.2 Velocity 2693 5.2.1 Optical Cross-correlation Sensors 2693 5.2.2 Laser Doppler Anemometry 2695 5.3 Stress 2695 5.4 Temperature 2696 5.5 Species Determination and Concentration 2697 5.5.1 Atomic Absorption Spectrometry 2697 5.5.2 Polarimetry 2698 5.6 Light Barriers 2699 5.6.1 Monostatic and Bistatic Light Barriers 2699 5.6.2 Smoke Detectors 2700 5.7 Surface Analysis 2700 5.7.1 Optical Cross-correlation Sensors 2700 5.7.2 Conoscopic Holography 2701 5.7.3 Photon-mixing Devices 2703 5.7.4 Triangulation Sensors 2703 5.8 Angular Velocity 2704 5.8.1 Fiber Gyroscopes 2704 5.8.2 Laser Gyroscope 2704 5.9 Rain Sensor 2705 6 Conclusion 2706 Glossary 2706 References 2707 Further Reading 2708 ÁËÎÊ_× SPECKLE AND SPECKLE METROLOGY 2709 0 KEYWORDS: speckle; speckle photography; speckle interferometry; * electronic speckle pattern interferometry; digital holography. 1 Introduction 2711 2 Some Statistical Properties 2712 2.1 First-order Statistics 2713 2.2 Second-order Statistics 2714 2.3 Integrated and Blurred Speckles 2715 3 Speckle Photography 2715 3.1 Speckle Displacement and Decorrelation 2716 3.2 Pointwise and Whole Field Filtering Method 2717 3.3 Fringe Analysis: Improvements and Limitations 2720 3.4 Tilt Measurement 2721 3.5 Rigid-body Displacement Out-of-plane 2722 3.6 Digital Speckle Photography 2722 3.7 Derivatives of Displacement 2723 3.8 White Light Speckle Photography 2724 4 Speckle Interferometry 2724 4.1 Basic Principle of Speckle Interferometry 2724 4.2 Sensitivity Vectors 2727 4.2.1 Single-beam Illumination-1 2727 4.2.2 Single-beam Illumination-2 2727 4.2.3 Single-beam Illumination-3 2727 4.2.4 Two-beam Illumination-1 2729 4.2.5 Two-beam Illumination-2 2729 4.2.6 Two-beam Illumination-3 2729 4.3 Out-of-plane Sensitive Interferometer 2729 4.3.1 Enhancement of Contrast 2730 4.3.2 Reduction of Sensitivity 2730 4.3.3 Comparative Speckle Interferometry 2731 4.4 In-plane Displacement Measurement 2732 4.4.1 Two-beam Illumination 2732 4.4.2 Double Aperture Camera 2734 4.4.3 Single-beam Illumination 2736 4.4.4 Multiple Aperture Arrangement for Simultaneous In-plane and Out-of-plane Components 2737 5 Speckle Shear Interferometry (Shearography) 2737 5.1 Modified Michelson Arrangement 2738 5.2 Double-aperture Methods 2739 5.3 Multiaperture Methods 2740 5.4 Radial and Rotational Shear 2741 5.5 Dual-beam Speckle Shearing Interferometer 2742 Speckle and Speckle Metrology 2711 6 Electronic Speckle Pattern Interferometry (ESPI) 2743 6.1 Background Concept 2744 6.1.1 Static Deformation 2745 6.1.2 Dynamic Deformation 2747 6.2 Development of ESPI 2748 6.3 Application of ESPI 2749 7 Contour Generation 2750 8 Temporal Speckle Pattern Interferometry (TSPI) 2752 8.1 Vibration Measurement 2757 9 Quantitative Evaluation 2758 10 Digital Holographic Interferometry 2761 10.1 Experimental Setup for Recording Digital Holograms 2762 10.2 Digital Reconstruction of the Hologram 2763 10.3 Pulsed Digital Holographic Interferometry 2764 11 Summary, Conclusion, and Limitation of Speckle Techniques 2765 References 2767 ÁËÎÊ_Ò V O L. V Spectrometers, Infrared - Zeeman and Stark Effects ÁËÎÊ_× SPECTROMETERS, INFRARED 2773 0 KEYWORDS: bolometer; detectivity; detector; Fourier transform spectrometer; grating spectrometer; * infrared radiation; infrared spectroscopy; interferometer; laser spectrometer; NEP; * photoacoustic effect; prism spectrometer; responsivity; sampling techniques; * spectrometer 1 Introduction 2776 2 General Aspects of Infrared Spectroscopy 2776 2.1 Infrared Radiation 2776 2.2 Infrared Absorption and Emission 2776 2.3 Infrared Spectra 2777 3 General Principle of Infrared Spectrometers 2778 3.1 Sample Compartment 2778 3.2 Wavelength Selector 2778 3.3 Optics 2779 3.4 Electronics 2779 3.5 Calibration 2780 3.6 Data Handling and Computation 2781 4 Detectors 2781 4.1 General Aspects of Infrared Radiation Detection 2781 4.1.1 Thermal Effects 2781 4.1.2 Photoacoustic Effects 2781 4.1.3 Photon Effects 2782 4.1.4 Rectification 2782 4.1.5 Charge-coupled Devices (CCDs) 2782 4.2 Detector Performance Criteria 2782 4.2.1 Noise in Detectors 2782 4.2.2 Responsivity 2784 4.2.3 Detectivity 2784 4.2.4 Quantum Efficiency 2784 4.2.5 Frequency Response 2784 4.2.6 Linearity and Dynamic Range 2785 4.2.7 Geometry 2785 4.2.8 Stability 2785 4.3 Types of Detectors 2785 4.3.1 Thermal Detectors 2785 Bolometers 2785 Pyroelectrics 2786 Thermopiles 2786 Golay Cells 2786 4.3.2 Photoacoustic Detectors 2786 4.3.3 Photon Detectors 2787 4.4 Detector Selection for Application to Broad-banded Spectroscopy 2788 4.4.1 Millimeter Region; 1 cm?1 to 10 cm?1 2788 4.4.2 Far-infrared (FIR); 10 cm?1 to 400 cm?1 2788 4.4.3 Mid-infrared (MIR); 400 cm?1 to 4000 cm?1 2788 4.4.4 Near-infrared (NIR); 4000 cm?1 to 13 200 cm?1 2788 4.4.5 Visible (VIS); 13 200 cm?1 to 25 000 cm?1 2788 Spectrometers, Infrared 2775 5 Performance Properties of Infrared Spectrometers 2789 6 Different Types of Infrared Spectrometers and their Performance Properties 2790 6.1 Prism Spectrometer 2790 6.2 Grating Spectrometer 2792 6.3 Fourier-transform Spectrometer 2795 6.3.1 Michelson Interferometer 2795 6.3.2 Collimated Beam and Extended Source in Michelson Interferometer 2796 6.3.3 Advantages of FT Spectrometers Compared to Grating Spectrometers 2798 Jacquinot Advantage (Throughput Advantage) 2798 Fellgett Advantage (Multiplex Advantage) 2798 Other Advantages 2799 6.3.4 Other Interferometers 2800 6.4 Laser Spectrometer 2801 7 Applications of Infrared Spectrometers 2802 7.1 Commonly used Analytical Sampling Techniques 2802 7.1.1 Transmission Spectroscopy 2803 7.1.2 External Reflection Spectroscopy 2804 7.1.3 Internal Reflection Spectroscopy 2808 7.1.4 Photoacoustic Spectroscopy 2809 7.1.5 Other Techniques 2809 7.2 Molecular Spectroscopy 2810 7.3 Dispersive FT-IR Spectrometry 2811 7.4 Hyphenated Techniques 2813 7.4.1 Chromatography-FT-IR 2813 7.4.2 Thermogravimetry-FT-IR 2814 7.5 Microscopy 2815 7.6 Imaging 2815 7.7 Modulation Techniques 2818 7.8 Time-resolved Spectroscopy (TRS) 2819 7.8.1 Rapid Scan TRS 2819 7.8.2 Step Scan TRS 2819 7.8.3 Interleaved Rapid Scan TRS 2823 7.9 FT-Raman 2823 7.10 Near-infrared Spectroscopy 2824 Acknowledgments 2826 Glossary 2826 References 2828 Further Reading 2830 ÁËÎÊ_× SPECTROMETERS, ULTRAVIOLET AND VISIBLE LIGHT 2831 0 KEYWORDS: spectrometer; grating; prism; interferometer; spectroscopy; absorption 1 Introduction 2833 2 Design Considerations 2835 2.1 Luminosity or ?Etendue 2835 2.2 Resolution 2835 2.3 Dispersion 2835 2.4 Efficiency 2836 3 Elements of a Generic Spectrometer 2836 3.1 Entrance Aperture 2836 3.2 Collimating Optics 2836 3.3 Wavelength-selecting Element 2837 3.4 Focusing Optics 2837 3.5 Exit Aperture 2837 3.6 Detector 2837 4 Prism Spectrometers 2838 4.1 Dispersion 2838 4.2 Resolution 2838 4.3 Luminosity 2839 4.4 Specialized Designs 2839 4.5 Aberrations 2840 4.5.1 Spherical Aberration 2840 4.5.2 Coma 2841 4.5.3 Astigmatism 2841 4.5.4 Curvature of Field 2842 4.5.5 Chromatic Aberration 2842 5 Grating Spectrometers 2842 5.1 Dispersion 2842 5.2 Resolution 2843 5.3 Luminosity 2843 5.4 Design and Manufacture of Gratings 2843 5.4.1 Transmission Grating 2844 5.4.2 Reflection Grating 2844 5.4.3 Echelles 2845 5.4.4 Holographic Gratings 2845 5.5 Plane Grating Spectrometers 2845 5.5.1 Aberrations 2845 Spherical aberration 2846 Coma 2846 Astigmatism 2846 Curvature of field 2847 5.5.2 Types of Plane Grating Spectrometers 2848 Ebert–Fastie 2848 Czerny–Turner 2848 Newtonian 2849 5.6 Concave Grating Spectrometers 2849 5.6.1 Optical Aberrations of Concave Mirrors 2849 5.6.2 Rowland Circle Mounts 2850 Paschen–Runge 2850 Eagle mount 2851 Grazing incidence 2851 5.6.3 Non-Rowland Circle Mounts 2852 Seya–Namioka 2852 Wadsworth 2852 Compensated holographic 2852 Spectrometers, Ultraviolet and Visible Light 2833 6 Interferometric Spectrometers 2853 6.1 Michelson 2853 6.2 Fabry–Perot 2853 7 Hybrid and Compound Instruments 2855 7.1 Order-sorter for a Grating Spectrometer 2855 7.2 Harrison Echelle 2856 7.3 Fabry–Perot/Grating Instrument 2856 7.4 Double and Triple Monochromators 2857 8 Detectors 2857 8.1 Ideal Detector 2857 8.2 Types of Detectors 2857 Photographic Plate 2857 Photomultipliers 2858 Photodiode 2859 Avalanche photodiode 2859 Diode array 2859 CCD 2860 9 Uses of UV–visible Spectrometers 2860 9.1 UV and Visible Absorption Spectroscopy 2860 9.1.1 Photometric Measurements 2860 9.1.2 Atomic Absorption Spectroscopy 2860 9.1.3 Structural Determinations 2861 9.1.4 Transient Molecules 2861 9.2 Emission Spectroscopy 2861 9.2.1 Atomic Emission 2861 9.2.2 Molecular Band Spectra 2862 9.2.3 Resonance Fluorescence 2862 9.3 Raman Spectroscopy 2862 Glossary 2862 References 2863 Further Reading 2863 ÁËÎÊ_× SPECTROMETERS, X-RAY 2865 0 KEYWORDS * crystal spectrometers; diffraction gratings; microcalorimeters; multilayers; * semiconductor detectors; X-ray detectors; X-ray imaging; X-ray spectrometry 1 Introduction 2866 2 General Concepts 2867 3 Dispersive Spectrometers 2868 3.1 Bragg Crystal Devices 2868 3.1.1 Bragg’s Law 2868 3.1.2 Flat Crystal Bragg Spectrometer 2869 3.1.3 Bent-crystal Spectrometer 2871 3.1.4 Bragg Spectroscopy with Synthetic Crystals (Multilayers) 2874 3.2 Diffraction Gratings 2876 4 Nondispersive (Energy-dispersive) Spectrometers 2878 4.1 Semiconductor Devices 2878 4.1.1 Lithium-drifted Silicon [Si(Li)] Detectors 2881 4.1.2 Germanium Detectors 2881 4.1.3 Silicon Drift Chamber Detectors 2882 4.1.4 Charge-coupled Devices (CCDs) 2882 4.1.5 Room-temperature Devices 2882 4.2 Cryogenic Devices 2883 5 Higher Energies (30 to 511 keV) 2885 6 Applications 2885 Acknowledgment 2886 Glossary 2886 References 2888 Further Reading 2888 ÁËÎÊ_× SPECTROSCOPY, ATOMIC 2891 0 KEYWORDS * lasers; atom sources; light spectroscopy; * atomic structure; laser spectroscopy; atomic spectroscopy. 1 Introduction 2894 2 Atom Structure 2895 3 Theory of Atomic Structure 2898 4 Many-electron Atoms 2899 4.1 Independent-particle Wave Functions 2899 4.2 Slater Determinants for an Atom with N Electrons 2900 4.3 Self-consistent Potential 2901 4.4 Perturbation Theory for Energy Levels 2901 5 Configurations, Terms, and Levels 2902 6 Configuration Interactions 2903 7 Hyperfine Structure and Isotope Shifts 2903 8 Interactions with External Magnetic and Electric Fields 2904 9 Radiative Transitions and Selection Rules 2904 10 Line Widths 2905 11 Light Sources 2907 11.1 Practical Line Sources 2907 11.1.1 The King Furnace 2907 11.1.2 Low-pressure Metal Vapor Lamps 2907 11.1.3 Hollow-cathode Lamps 2907 11.1.4 Microwave-driven Lamps 2908 11.2 Practical Continuum Sources 2908 11.2.1 Blackbody Sources 2908 Spectroscopy, Atomic 2893 11.2.2 The Sun 2909 11.2.3 Flames 2909 11.2.4 Nernst Glowers 2910 11.2.5 Globar 2910 11.2.6 Furnaces 2910 11.2.7 Continuous Discharge Lamps 2910 11.2.8 Filament Lamps 2910 11.2.9 Flashlamps 2912 11.3 Light-emitting Diodes 2912 11.4 Lasers 2912 11.4.1 Pump Lasers 2913 11.4.2 Tunable Lasers 2914 11.4.2.1 Dye Lasers 2914 11.4.2.2 Semiconductor Lasers 2914 11.4.2.3 Tunable Solid Lasers 2915 11.4.2.4 Quantum Cascade Lasers 2915 11.4.2.5 Femtosecond Lasers 2915 11.5 Nonlinear Optical Frequency Converters 2916 11.5.1 Nonlinear Mixing in Bulk Crystals 2917 11.5.2 Optical Parametric Oscillators 2917 12 Atom Sources 2918 12.1 Simple Cells 2918 12.2 Flames 2918 12.3 Electrothermal Atomizers 2919 12.4 Heat Pipes 2920 12.5 Atomic Beams 2921 12.5.1 Effusive Beams 2921 12.5.2 Supersonic Nozzle Beams 2923 12.5.3 Other Beam Methods 2925 12.6 Atom Traps 2926 12.6.1 Ion Traps 2926 12.6.2 Magneto-optical Atom Traps 2927 12.6.3 Magnetic Traps 2927 12.6.4 Atomic Fountain 2928 13 Spectrometers 2928 13.1 Prism and Grating Spectrometers 2930 13.1.1 Prisms 2930 13.1.2 Gratings 2932 13.2 Fabry–Perot Interferometers and Etalons 2935 13.3 Filters 2937 14 Detectors of Light 2938 14.1 Responsivity 2939 14.2 Noise 2939 14.3 Thermal Detectors 2940 14.3.1 Thermocouples 2940 14.3.2 Bolometers 2941 14.3.3 Pyroelectric Detectors 2942 14.4 Photon Detectors 2942 14.4.1 Photoemissive Detectors 2942 14.4.2 Photoconductive Detectors 2943 14.4.3 Photovoltaic Detectors 2946 14.4.4 Arrays 2948 14.5 Single-photon Counting Modules 2948 15 Laser Spectroscopy Applications 2949 15.1 Single-molecule Detection 2949 15.2 Cavity-ringdown Laser Absorption Spectroscopy 2950 15.3 Femtosecond-comb Spectroscopy 2952 Acknowledgments 2952 Glossary 2952 References 2954 Further Reading 2955 ÁËÎÊ_× SPECTROSCOPY, LASER 2957 0 KEYWORDS * lasers; atoms; molecules; spectroscopy. 1 Introduction 2958 2 Widths of Spectral Lines 2962 2.1 Mechanisms of Line Broadening 2963 2.1.1 Homogeneous Broadening 2963 2.1.2 Inhomogeneous Broadening 2963 3 High-resolution Spectroscopy 2965 3.1 Saturation Spectroscopy 2967 3.2 Intermodulated Spectroscopy 2969 3.3 Polarization Spectroscopy 2971 3.4 Velocity-selective Optical-pumping Spectroscopy 2974 3.5 Polarization-intermodulated Excitation Spectroscopy (POLINEX) 2974 3.6 Multiphoton Spectroscopy 2976 3.6.1 Selection Rules for Two-photon Transitions 2978 3.6.2 Transition Probabilities and Line Shapes for Two-photon Transitions 2978 3.6.3 Doppler-free Multiphoton Transitions 2981 3.6.4 Applications of High-resolution Spectroscopic Techniques to the Hydrogen Atom * Lamb-shift and Rydberg-constant Measurements 2982 4 High-sensitivity Laser Spectroscopy 2984 4.1 Excitation Spectroscopy 2986 4.2 Optoacoustic Spectroscopy 2987 4.3 Optogalvanic Spectroscopy 2988 4.4 Intracavity Spectroscopy 2991 4.5 Fast Modulation Spectroscopy 2993 5 Time-resolved Spectroscopy 2995 5.1 Lifetime Measurements 2996 5.1.1 Phase-shift Method 2996 5.1.2 Pulse Excitation 2997 5.2 Quantum-beat Spectroscopy 2997 6 Spectroscopy with Cold Atoms 3000 6.1 Laser Cooling 3001 6.2 Experimental Arrangements 3003 6.3 Optical Molasses 3006 Induced Dipole Forces in a Radiation Field 3007 6.4 Magneto-optical Trap 3008 6.5 Cooling of Molecules 3010 6.6 Applications of Cooled Atoms and Molecules 3011 6.7 Spectroscopy of Single Ions 3014 Glossary 3016 References 3017 Further Reading 3019 ÁËÎÊ_× SPECTROSCOPY, PHOTOACOUSTIC 3021 0 KEYWORDS * photoacoustic; photothermal; tracegas detection; * solid state spectroscopy; material testing; calorimetry; life science. 1 Introduction 3022 2 Devices and Equipment 3024 2.1 Light Sources 3024 2.2 Gas-phase Photoacoustic Cells 3026 2.2.1 Nonresonant Cells 3027 2.2.2 Resonant Cells 3027 2.3 Condensed-matter Photoacoustic Cells 3032 2.4 Photothermal Detection 3032 2.4.1 Photothermal Deflection Spectroscopy 3032 2.4.2 Thermal Lensing 3035 2.5 Fourier-transformed Infrared Photoacoustic Spectroscopy 3035 3 Application 3036 3.1 Photoacoustic Spectroscopy in the Condensed Phase 3036 3.1.1 Solid-state Spectroscopy 3037 3.1.2 Depth Profiling 3038 3.1.3 Thermal Diffusivity 3038 3.1.4 Phase Transitions 3039 3.1.5 Traces in Solution 3039 3.1.6 Chemical Reactions 3039 Calorimetry 3039 V o l u m e Effect 3040 Time Resolution 3040 3.1.7 Biological Processes in Solution 3041 3.2 Photoacoustic Spectroscopy in the Gas Phase 3041 3.2.1 Overtone Studies 3041 3.2.2 Relaxation 3043 3.3 Trace Gas Detection 3045 3.3.1 Environmental applications 3046 3.3.2 Plant Physiology 3047 3.3.3 Entomology 3049 3.3.4 Human Health Research 3051 Acknowledgment 3052 Glossary 3052 References 3055 Further Reading 3056 ÁËÎÊ_× SPECTROSCOPY, RAMAN 3057 0 KEYWORDS: Raman spectroscopy; materials characterization; applications, art history; * biomedical diagnostics; archeology; environmental science; astrobiology. 1 Introduction 3059 2 Theory 3060 2.1 Intensity Measurements in Raman Scattering 3061 2.2 Nonlinear Raman Spectroscopy 3062 2.2.1 Induced Electric Dipole-frequency Mixing (Nonlinear Polarization) 3062 2.2.2 Hyper-Rayleigh and Hyper-Raman Scattering 3063 2.2.3 CARS 3063 2.2.4 SRGS (SRLS) 3066 2.3 Special Techniques in Raman Spectroscopy 3066 2.3.1 Surface-enhanced Raman Scattering 3066 2.3.2 Photoacoustic Raman Spectroscopy (PARS) 3067 2.4 Spectra-structure Correlations in Raman Spectroscopy 3068 2.4.1 Factors That Affect Raman Band Parameters 3068 2.4.2 Effect of Adjacent Groups on Vibrational Wave Numbers 3070 The Carbonyl Bond(s) 3070 Factors That Affect Carbonyl Bond Wave-numbers 3070 Mass effects 3070 Bond geometry effects 3071 Electronic effects 3071 3 Instrumentation 3072 3.1 Instrumentation for the Generation, Illumination, Dispersion, and Detection of Electromagnetic Radiation of Relevance to Raman Spectroscopy 3075 3.1.1 Electromagnetic-radiation Sources 3075 3.1.2 Lasers 3075 3.1.3 Sample Illuminator and Cell Design 3077 3.1.4 Spectrometers and the Dispersion of Radiation 3082 Dispersion 3082 Resolving Power 3082 Brightness of Image 3083 Speed of Spectrograph/Spectrometer 3083 Slit 3083 Collimator 3084 Diffraction Grating 3084 Camera Mirror/Lens 3086 Detectors 3086 Problems 3087 Light leakage 3087 Effect of temperature, pressure and humidity 3087 Spectral line tilt 3088 Calibration 3088 3.2 Raman Microscopy and Imaging Techniques 3092 3.2.1 CCD Devices 3094 3.2.2 Confocal Microscopy 3095 3.2.3 Raman Imaging and Mapping 3096 3.2.4 The UV Microscope 3096 3.2.5 Raman Microspectroscopy with Near-infrared Excitation 3097 3.3 Raman Imaging 3098 3.3.1 Line Imaging 3099 3.3.2 Wide-field Imaging 3101 3.3.3 Raman Imaging Fiberscopes 3102 Spectroscopy, Raman 3059 3.4 Fourier-transform (FT) Methods in Vibrational Spectroscopy 3103 3.4.1 Conventional Raman and Fourier-transform Raman Spectroscopy 3108 4 Illustrative Examples 3109 4.1 Raman Spectroscopy and Art 3109 4.2 Biomaterials in Archaeology 3113 4.2.1 Resins 3113 4.2.2 Ivories 3115 4.3 Geological Materials 3120 4.3.1 Extraterrestrial Studies 3120 4.3.2 Martian Meteorites 3123 4.3.3 Antarctic Biological Modifications 3124 4.4 Remote-sensing Probes 3126 4.5 Biodiagnostics 3128 Glossary 3132 References 3133 3135_× SPECTROSCOPY, ULTRAFAST 0 KEYWORDS: ultrashort pulses; wave packet; coherent; femtosecond; ultrafast; picosecond; * time-resolved. 1 Introduction 3136 2 Physical Framework and Examples 3138 2.1 Illustrative Example 3140 2.2 Applications 3142 3 Experimental Techniques and Methods 3145 3.1 Ultrafast Laser Systems 3145 3.2 Detection in Ultrafast Spectroscopy: The Pump–probe Method 3146 4 Ultrafast Spectroscopy of Molecules 3147 4.1 Ultrafast Rotational Spectroscopy 3148 4.2 Ultrafast Vibrational Spectroscopy 3150 4.3 Coherence and Dephasing 3151 5 Chemical Reactions 3153 5.1 Unimolecular Photodissociation along a Single Reaction Coordinate 3153 5.2 Unimolecular Photodissociation along Multiple Reaction Coordinates 3154 5.3 Other Unimolecular Reactions 3156 5.4 Bimolecular Reactions 3158 6 Other Applications of Ultrafast Spectroscopy 3159 6.1 Liquids 3160 6.2 Solids 3163 6.3 Biological 3163 Glossary 3165 References 3166 Further Reading 3167 ÁËÎÊ_× STEREOSCOPY 3169 0 KEYWORDS: stereoscopic principles; stereoscopic image-generation techniques; * stereoimage display; measurement in stereoimages; stereoplotters; orthophotos; * least-squares matching; feature-based matching; digital elevation models. 1 Introduction 3170 2 Principles of Stereoscopic Imaging 3171 2.1 Historical Review of Stereo Viewing 3171 2.2 Technical Principle 3172 3 Stereoscopic Image-Generation Techniques 3173 3.1 Basic Techniques 3173 3.1.1 Conventional Photographs and Movies 3173 3.1.2 Electronic Images 3173 3.2 Requirements 3174 3.2.1 Visualization 3174 3.2.2 Measurement 3177 4 Methods of Stereoimage Display 3178 4.1 Viewing of Stereophotographs and Stereomovies 3178 4.1.1 Viewing by Geometric Separation of Stereo Pairs 3178 4.1.2 Anaglyphs 3179 4.1.3 Polarization 3179 4.1.4 Autostereoscopic Viewing of Stereo Pairs 3180 4.2 Viewing of Electronic Stereo Pairs 3181 4.2.1 Viewing by Geometric Separation of Stereo Pairs 3181 4.2.2 Anaglyphs 3181 4.2.3 Shutter Glasses 3181 4.2.4 Polarization 3182 4.2.5 Autostereoscopic Displays 3183 4.3 Other 3D Techniques 3184 4.3.1 Holography 3184 4.3.2 Depth Cue by the Pulfrich Effect 3185 4.3.3 Volumetric Displays 3185 4.3.4 Single-image Stereograms 3185 5 Measurement in Stereoimages 3186 5.1 Historical Review of Stereo Measurement 3186 5.2 Image Interpretation with Analog and Analytical Instrumentation 3187 5.2.1 Stereoplotters 3187 Digital Elevation Models 3189 Orthophotos 3190 5.3 Coordinate Measurements in Stereo Images 3190 5.4 Point Transfer by Digital Image Correlation 3194 5.4.1 Least-squares Matching 3194 5.4.2 Feature-based Matching 3195 5.4.3 Measurement in Multiple Images 3196 5.4.4 Applications 3197 Digital Elevation Models and Orthophotos 3197 Semiautomatic Interpretation 3198 Glossary 3199 References 3199 Further Reading 3200 ÁËÎÊ_× ULTRASHORT-PULSE PHENOMENA 3201 0 KEYWORDS: ultrashort-pulse phenomena; ultrafast lasers; femtosecond pulses; * ultrashort-pulse characterization; active and passive mode locking; frequency conversion; * pump-and-probe measurements. 1 Introduction 3202 2 Ultrashort-pulse Propagation 3203 3 Generation of Ultrashort Pulses 3204 3.1 Basic Ultrafast Laser Sources 3204 3.1.1 Mode-locked Rhodamine 6 G Dye Lasers 3206 3.1.2 Mode-locked Ti:Sapphire Lasers 3207 3.1.3 Other Materials for Ultrashort-pulse Generation 3208 3.1.4 Mode-locked Fiber Lasers 3209 3.1.5 Mode-locked Semiconductor Lasers 3210 3.2 Amplified Ultrashort Pulses 3210 3.3 Frequency-conversion Devices 3212 3.3.1 Ultrafast Considerations 3213 3.3.2 Ultrafast Nonlinear Optical Devices 3214 4 Femtosecond Measurement Techniques 3214 4.1 Autocorrelation Technique 3214 4.2 Frequency Resolved Optical Gating (FROG) Technique 3216 4.3 Spectral Phase Interferometry for Direct Electric Field Reconstruction (SPIDER) 3218 4.4 Pump-and-probe Measurement Techniques 3219 4.5 Optical Correlation Spectroscopy 3220 5 Applications of Ultrashort Pulses 3222 5.1 Femtosecond Relaxation in Bulk Semiconductors and Quantum-well Structures 3222 5.2 Femtosecond Relaxation Dynamics in Molecules 3224 5.3 Coherent Wave-packet Excitation and Relaxation in Molecules 3224 5.4 Coherent Wave-packet Excitation and Relaxation in Coupled Quantum Wells 3226 5.5 THz Generation 3226 5.6 High Harmonic Generation and Attosecond Pulses 3227 5.7 Carrier-envelope Phase Stabilization 3228 5.8 Multiphoton Processes 3229 Glossary 3230 References 3231 Further Reading 3236 ÁËÎÊ_× UNDERWATER OPTICS 3237 0 KEYWORDS * scattering; underwater light field; remote sensing; underwater imaging. 1 Introduction 3238 2 Inherent Optical Properties of Water (IOP) 3240 2.1 Definitions 3240 2.2 Methods of Measuring the IOP 3242 2.3 Physical Factors of IOP 3243 2.4 Data on Spatial and Spectral Distribution of IOP in Natural Waters 3244 2.5 Few parametric Models of IOP 3246 2.5.1 Physical Models 3246 2.5.2 Empirical Models 3247 2.5.3 Simplified Semiempirical Models 3248 3 The Underwater Light Fields (ULF) 3248 3.1 Radiative Transfer Equation (RTE) and the Methods of Solving it 3249 3.2 Solar Radiation in the Sea 3250 3.3 Artificial ULF 3252 3.3.1 Narrow Light Beam 3252 3.3.2 ULF from an Isotropic Source 3254 3.3.3 Propagation of a Light Pulse 3256 3.3.4 Backscattering 3256 3.4 Influence of the Sea Surface on Light Fields 3257 4 Optical Methods for Investigation of the Ocean and Other Natural Waters 3258 4.1 Detection of Phytoplankton and of Suspended and Dissolved Matter 3258 4.2 Optical Methods for Investigation of the Sea Surface 3259 4.3 Laser Remote Sensing of the Ocean 3260 4.4 Atmospheric Corrections of Satellite-measured Data of Ocean Remote Sensing 3260 5 Underwater Imaging 3261 5.1 ‘‘Classic’’ Duntley–Preisendorfer Visibility Theory 3262 5.2 Image Transfer Theory 3263 5.3 Sighting Range and Spatial Resolution in Water 3265 Glossary 3267 References 3269 Further Reading 3271 ÁËÎÊ_× WAVE OPTICS 3273 0 KEYWORDS * wave-propagation; interference; diffraction; holography; phase-retrieval; self-imaging; * helical light; phase-conjugation 1 Introduction 3274 2 The Wave Equation 3275 2.1 Definitions 3275 2.2 The Maxwell Equations (in MKS Units) 3275 2.3 The Source-driven Wave Equation 3276 3 Optical Propagation in Free Space 3277 3.1 Fourier Transform Definitions 3278 3.2 Propagation Between Two Parallel Planes 3278 3.3 Propagation from Complicated Surfaces 3280 3.3.1 An Example * Propagation from the x–y Plane into the Right Half Space 3280 3.3.2 Differential Expressions for Severed 3-D Vector Fields 3282 3.4 Optical Propagation Through Materials 3283 3.4.1 The Born Approximation 3283 3.4.2 The Lumped-element Model of Propagation 3283 3.4.3 Split-step and Ping-pong Propagation 3284 3.5 Angular Components of Waves 3284 3.5.1 Circular Harmonic Decomposition 3284 3.5.2 The Fourier Transform in Polar Coordinates 3284 3.5.3 Hankel Transform 3285 3.5.4 Optical Propeller Beams 3285 3.5.5 Diffraction-free Beams 3285 4 Interference 3287 5 Diffraction Gratings 3288 6 Holograms 3290 6.1 Selected Events in the History of Holography 3290 6.2 Interferometric Holograms 3291 6.3 Computer-generated Holograms 3291 6.3.1 Point-oriented CGHs 3292 The Perfect CGH 3292 The Kinoform 3292 The Cosine CGH 3292 6.3.2 Cell-oriented CGHs 3293 7 Phase Conjugation 3294 8 The Talbot Effect 3296 8.1 Strong Self-imaging – Exact Talbot Objects 3296 8.2 Weak Self-imaging 3297 8.3 The Fractional Talbot Effect 3298 8.4 Grating Walk-off 3299 8.5 The Lau Effect 3299 9 Phase Retrieval 3299 Glossary 3300 References 3303 ÁËÎÊ_× X-RAY OPTICS 3305 0 KEYWORDS * X rays; grazing incidence; crystals; compound refractive lenses; multilayers; diffraction; * zone plates; sources; applications. 1 Introduction 3307 2 X-ray Sources 3309 2.1 X-ray Emission Processes 3310 2.2 Microfocus Sources 3310 2.3 Synchrotron Radiation Sources 3310 2.4 Plasma Sources 3312 2.4.1 Laser-generated Plasmas 3312 2.4.2 Pinch Plasmas 3313 2.5 XUV Lasers 3314 2.5.1 Plasma-based XUV Lasers 3314 2.5.2 Free-electron Lasers 3314 2.5.3 High-harmonic Generation 3314 2.6 Other X-ray Emission Processes 3315 2.6.1 Channeling Radiation 3315 2.6.2 Transition Radiation 3315 2.6.3 Parametric Radiation 3315 3 X-ray Interactions 3315 3.1 Thomson Scattering 3318 3.2 Anomalous Dispersion 3319 3.3 The Atomic Scattering Factors and Optical Constants 3319 3.3.1 The Lorentz Model for the Optical Constants 3320 3.3.2 Kramers–Kronig Analysis 3321 4 Grazing Incidence X-ray Optics 3323 4.1 The Fresnel Equations 3323 4.2 Reflection of X rays from Rough Surfaces 3325 4.3 Aberrations of Grazing Incidence Optics 3327 4.3.1 Astigmatism 3327 4.3.2 Spherical Aberration 3328 4.3.3 Coma 3328 4.3.4 Reduction of Aberrations 3329 4.3.5 Aspheric Reflectors 3329 4.4 Compound Systems 3329 4.4.1 Kirkpatrick–Baez Optics 3330 4.4.2 Wolter Optics 3330 4.5 Manufacture of Grazing Incidence Optics 3331 4.6 X-ray Optical Arrays 3331 5 Crystal and Multilayer Optics 3332 5.1 Crystal Diffraction 3332 5.1.1 The Reciprocal Lattice 3333 5.1.2 The Ewald Sphere 3334 5.1.3 The Phase Problem 3334 5.2 Crystal Optics 3336 5.3 Multilayer Mirrors 3337 5.3.1 Multilayer Reflectivity 3338 5.3.2 The Effect of Roughness on Multilayer Reflectivity 3341 5.3.3 Manufacture of Multilayer Mirrors 3341 5.3.4 Multilayer Supermirrors 3343 6 Compound Refractive Lenses 3345 6.1 Focal Length 3346 6.2 Resolution, Transmission, and Gain 3346 7 Diffractive X-ray Optics 3347 7.1 Diffraction Gratings 3348 7.2 Zone Plates 3350 7.2.1 Geometry of a Zone Plate 3351 7.2.2 Zone Plates as Thin Lenses 3352 7.2.3 Diffraction Efficiencies of Zone Plates 3353 Amplitude Zone Plates 3353 Phase Zone Plates 3354 X-ray Optics 3307 7.2.4 Manufacture of Zone Plates 3357 Electron-beam Lithography 3357 Interference (Holographic) Methods 3357 The Sputter and Slice Technique 3358 8 Bragg–Fresnel Lenses 3358 8.1 Properties of Bragg–Fresnel Lenses 3358 8.2 Manufacture of Bragg–Fresnel Lenses 3360 9 Applications of X-ray Optics 3360 9.1 Overview of Applications 3360 9.2 X-ray Microscopy 3361 9.2.1 X-ray Microscopy Without Optics 3361 9.2.2 Transmission X-ray Microscopy 3362 9.3 X-ray Microprobes 3364 10 Further Topics in X-ray Optics 3365 Acknowledgments 3366 Glossary 3366 References 3367 Further Reading 3371 ÁËÎÊ_× ZEEMAN AND STARK EFFECTS 3373 0 KEYWORDS * atomic spectroscopy; atomic structure; Larmor frequency; line shifts; line splittings; * electric dipole transitions; magnetic dipole transitions; polarization; Rydberg atoms. 1 Introduction 3374 2 Electric and Magnetic Fields Implications of Symmetry 3375 3 Zeeman Effect 3376 3.1 Historical Perspective 3376 3.2 Classical Explanation of the Zeeman Effect 3378 3.3 Quantum Structure of the Atom 3380 3.3.1 One-electron Atoms 3381 3.3.2 Multielectron Atoms 3382 3.4 The Atom in a Uniform Magnetic Field 3383 3.5 Weak-field Zeeman Effect 3385 3.5.1 Normal Zeeman Effect 3386 3.5.2 Anomalous Zeeman Effect 3388 3.6 Strong- and Ultrastrong-field Zeeman Effects 3389 4 Stark Effect 3392 4.1 Historical Perspective 3392 4.2 The Linear Stark Effect 3393 4.3 The Quadratic Stark Effect 3395 4.4 The ac Stark Effect 3396 5 ‘‘Exciting’’ Applications 3397 5.1 Rydberg Atoms in Electric & Magnetic Fields 3397 5.2 Magnetic Fields in the Cosmos 3400 Glossary 3402 References 3403 Further Reading 3403 // @