Matt Young Optics and Lasers Including Fibers and Optical Waveguides Fourth Revised Edition With 188 Figures Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong Barcelona Budapest
Contents 1. Introduction 1 2. Ray Optics 5 2.1 Reflection and Refraction 5 2.1.1 Refraction 5 2.1.2 Index of Refraction 6 2.1.3 Reflection 7 2.1.4 Total Internal Reflection 7 2.1.5 Reflecting Prisms 8 2.2 Imaging 9 2.2.1 Spherical Surfaces 9 2.2.2 Object-Image Relationship 11 2.2.3 Use of the Sign Convention 13 2.2.4 Lens Equation 13 2.2.5 Classification of Lenses and Images 15 2.2.6 Spherical Mirrors 16 2.2.7 Thick Lenses 17 2.2.8 Image Construction 19 2.2.9 Magnification 20 2.2.10 Newton's Form of the Lens Equation 22 2.2.11 Lagrange Invariant 23 2.2.12 Aberrations 23 Problems 24 3. Optical Instruments 27 3.1 The Eye (as an Optical Instrument) 27 3.2 Basic Camera 30 3.2.1 Photographic Emulsion 31 3.2.2 Sensitometry 32 3.2.3 Resolving Power 35 3.2.4 Depth of Field 35 3.3 Projection Systems 36 3.4 Hand Lens or Simple Magnifier 38 3.5 Microscope 39
X Contents 3.6 Scanning Confocal Microscope 41 3.6.1 Nipkow Disk 42 3.7 Telescope 43 3.7.1 Pupils and Stops 44 3.7.2 Field Stop 46 3.7.3 Terrestrial Telescopes 46 3.8 Resolving Power of Optical Instruments 47 3.8.1 Camera 47 3.8.2 Telescope 48 3.8.3 Microscope 49 3.8.4 Condensers 50 Problems 51 4. Light Sources and Detectors 55 4.1 Radiometry and Photometry 55 4Л.1 Radiometric Units 55 4.1.2 Photometric Units 57 4.1.3 Point Source 58 4.1.4 Extended Source 59 4.1.5 Diffuse Reflector 60 4.1.6 Integrating Sphere 61 4.1.7 Image Illuminance 63 4.1.8 Image Luminance 65 4.2 Light Sources 67 4.2.1 Blackbodies 67 4.2.2 Color Temperature and Brightness Temperature 71 4.2.3 Line Sources 71 4.2.4 Light-Emitting Diodes (LEDs) 74 4.3 Detectors 75 4.3.1 Quantum Detectors 75 4.3.2 Thermal Detectors 80 4.3.3 Detector Performance Parameters 82 Problems 85 5. Wave Optics 88 5.1 Waves 88 5.1.1 Electromagnetic Waves 90 5.1.2 Complex-Exponential Functions 90 5.2 Superposition of Waves 91 5.2.1 Group Velocity 92 5.2.2 Group Index of Refraction 93 5.3 Interference by Division of Wavefront 94 5.3.1 Double-Slit Interference 94 5.3.2 Multiple-Slit Interference 96
Contents XI 5.4 Interference by Division of Amplitude 98 5.4.1 Two-Beam Interference 98 5.4.2 Multiple-Reflection Interference 100 5.5 Diffraction 102 5.5.1 Single-Slit Diffraction 104 5.5.2 Interference by Finite Slits 106 5.5.3 Fresnel Diffraction 107 5.5.4 Far and Near Field 110 5.5.5 Babinet's Principle 112 5.5.6 Fermat's Principle 112 5.6 Coherence 114 5.6.1 Temporal Coherence 115 5.6.2 Spatial Coherence 116 5.6.3 Coherence of Thermal Sources 117 5.6.4 Coherence of Microscope Illumination 117 5.7 Theoretical Resolution Limit 118 5.7.1 Two-Point Resolution 119 5.7.2 Coherent Illumination 120 5.7.3 Diffused, Coherent Illumination 121 5.7.4 Quasi-Thermal Source 124 Problems 124 6. Interferometry and Related Areas 129 6.1 Diffraction Grating 129 6.1.1 Blazing 131 6.1.2 Chromatic Resolving Power 131 6.2 Michelson Interferometer 132 6.2.1 Twyman-Green Interferometer 134 6.2.2 Mach-Zehnder Interferometer 135 6.3 Fabry-Perot Interferometer 136 6.3.1 Chromatic Resolving Power 136 6.3.2 Free Spectral Range 138 6.3.3 Confocal Fabry-Perot Interferometer 139 6.4 Multilayer Mirrors and Interference Filters 139 6.4.1 Quarter-Wave Layer 139 6.4.2 Multilayer Mirrors 140 6.4.3 Interference Filters 140 Problems 141 7. Holography and Image Processing 143 7.1 Holography 143 7.1.1 Off-Axis Holography 146 7.1.2 Zone-Plate Interpretation 147
XII Contents 7.1.3 Amplitude and Phase Holograms 148 7.1.4 Thick Holograms 149 7.2 Optical Processing 151 7.2.1 Abbe Theory 152 7.2.2 Fourier Series 154 7.2.3 Fourier-Transform Optics 157 7.2.4 Spatial Filtering 158 7.2.5 Phase Contrast 162 7.2.6 Matched Filter 164 7.2.7 Converging-Beam Optical Processor 166 7.3 Impulse Response and Transfer Function 168 7.3.1 Impulse Response 168 7.3.2 Edge Response 170 7.3.3 Impulse Response of the Scanning Confocal Microscope 171 7.3.4 Image Restoration 173 7.3.5 Optical Transfer Function 175 7.3.6 Coherent Transfer Function 176 7.3.7 Diffraction-Limited Transfer Functions 176 7.3.8 MTF of Photographic Films 179 7.4 Digital Image Processing 179 7.4.1 Video Camera 179 7.4.2 Single-Pixel Operations 180 7.4.3 Cross-Correlation 182 7.4.4 Video Microscope 184 7.4.5 Dimensional Measurement 186 Problems 187 8. Lasers 192 8.1 Amplification of Light 192 8.1.1 Optical Amplifier 193 8.2 Optically Pumped Laser 196 8.2.1 Rate Equations 197 8.2.2 Output Power 198 8.2.3 Q-Switched Laser 198 8.2.4 Mode-Locked Laser 200 8.3 Optical Resonators 202 8.3.1 Axial Modes 202 8.3.2 Transverse Modes 204 8.3.3 Gaussian Beams 205 8.3.4 Stability Diagram 208 8.3.5 Coherence of Laser Sources 209 8.4 Specific Laser Systems 210 8.4.1 Ruby Laser 210
Contents XIII 8.4.2 Neodymium Laser 212 8.4.3 Organic-Dye Lasers 214 8.4.4 Helium-Neon Laser 215 8.4.5 Ion Lasers 216 8.4.6 C0 2 Laser 217 8.4.7 Other Gas Lasers 218 8.4.8 Semiconductor Lasers 218 8.5 Laser Safety 219 8.5.1 Sunglasses 221 Problems 221 9. Electromagnetic and Polarization Effects 224 9.1 Reflection and Refraction 224 9.1.1 Propagation 224 9.1.2 Brewster's Angle 225 9.1.3 Reflection 226 9.1.4 Interface between Two Dense Media 228 9.1.5 Internal Reflection 228 9.1.6 Phase Change 229 9.1.7 Reflection from Metals 231 9.2 Polarization 231 9.2.1 Birefringence 232 9.2.2 Wave Plates 233 9.2.3 Glan-Thompson and Nicol Prisms 235 9.2.4 Dichroic Polarizers 236 9.2.5 Optical Activity 236 9.2.6 Liquid Crystals 237 9.3 Nonlinear Optics 238 9.3.1 Second-Harmonic Generation 239 9.3.2 Phase Matching 240 9.3.3 Optical Mixing 242 9.4 Electro-optics, Magneto-optics and Acousto-optics 243 9.4.1 Kerr Effect 243 9.4.2 Pockels Effect 244 9.4.3 Electro-optic Light Modulation 245 9.4.4 Acousto-optic Beam Deflection 246 9.4.5 Faraday Effect 247 Problems 248 10. Optical Waveguides 250 10.1 Rays in Optical Fibers 250 10.2 Modes in Optical Waveguides 252 10.2.1 Propagation Constant and Phase Velocity 255 10.2.2 Prism Coupler. 256
XIV Contents 10.2.3 Grating Coupler 257 10.2.4 Modes in Circular Waveguides 259 10.2.5 Number of Modes in a Waveguide 259 10.2.6 Single-Mode Waveguide 260 10.3 Graded-Index Fibers 261 10.3.1 Parabolic Profile 261 10.3.2 Local Numerical Aperture 263 10.3.3 Leaky Rays 264 10.3.4 Restricted Launch 265 10.3.5 Bending Loss and Mode Coupling 267 10.4 Connectors 268 10.4.1 Multimode Fibers 269 10.4.2 Single-Mode Fibers 272 10.4.3 Star Couplers 274 Problems 275 11. Optical-Fiber Measurements 278 11.1 Launching Conditions 278 11.1.1 Beam-Optics Launch 279 11.1.2 Equilibrium Mode Simulator 279 11.1.3 Cladding-Mode Stripper 280 11.2 Attenuation 281 11.2.1 Attenuation Measurements 282 11.3 Fiber Bandwidth 284 11.3.1 Distortion 284 11.3.2 Material Dispersion 285 11.3.3 Waveguide Dispersion 285 11.3.4 Bandwidth Measurements 286 11.3.5 Coherence Length of the Source 287 11.4 Optical Time-Domain Reflectometry 288 11.5 Index Profile 290 11.5.1 Transverse Methods 290 11.5.2 Longitudinal Methods 291 11.5.3 Near-Field Scanning 292 11.5.4 Refracted-Ray Method 293 11.5.5 Core-Diameter Measurements 295 11.6 Numerical-Aperture Measurements 296 Problems 297 12. Integrated Optics 300 12.1 Optical Integrated Circuits 300 12.1.1 Channel or Strip Waveguides 302 12.1.2 Ridge Waveguide 303 12.1.3 Branches 304
Contents XV 12.1.4 Distributed-Feedback Lasers 305 12.1.5 Couplers 306 12.1.6 Modulators and Switches 307 12.2 Planar Optical Devices 310 12.2.1 Mode-Index Lenses 311 12.2.2 Lüneburg Lenses 312 12.2.3 Geodesic Lenses 313 12.2.4 Gratings 316 12.2.5 Surface-Emitting Lasers 319 Problems 320 Suggested Reading Material 323 Subject Index 328