Colour and the Optical Properties of Materials: An Exploration of the Relationship Between Light, the Optical Properties of Materials and Colour

Colour and the Optical Properties of Materials: An Exploration of the Relationship Between Light, the Optical Properties of Materials and Colour......Page 2
Contents......Page 10
Preface......Page 18
1.1 Colour and Light......Page 20
1.2 Colour and Energy......Page 22
1.3 Light Waves......Page 24
1.4 Interference......Page 26
1.5 Light Waves and Colour......Page 28
1.6 Black-Body Radiation and Incandescence......Page 29
1.7 The Colour of Incandescent Objects......Page 32
1.8 Photons......Page 33
1.9.1 Lamps......Page 35
1.9.3 Energy-level populations......Page 36
1.9.4 Rates of absorption and emission......Page 37
1.9.5 Cavity modes......Page 40
1.10 Vision......Page 42
1.11 Colour Perception......Page 47
1.12 Additive Coloration......Page 48
1.13 The Interaction of Light with a Material......Page 52
1.14 Subtractive Coloration......Page 56
1.15 Electronic ‘Paper’......Page 58
1.16 Appearance and Transparency......Page 59
A1.1.2 Waves......Page 62
A1.1.3 SI units associated with radiation and light......Page 64
Further Reading......Page 66
2.1 Refraction and the Refractive Index of a Material......Page 68
2.2.2 Evanescent waves......Page 73
2.3 Refractive Index and Polarisability......Page 77
2.4 Refractive Index and Density......Page 79
2.5 Invisible Animals, GRINs and Mirages......Page 81
2.6 Dispersion and Colours Produced by Dispersion......Page 84
2.7 Rainbows......Page 87
2.9.1 Optical communications......Page 94
2.9.2 Optical fibres......Page 96
2.9.3 Attenuation in glass fibres......Page 98
2.9.4 Chemical impurities......Page 99
2.9.5 Dispersion and optical-fibre design......Page 100
2.10.1 Metamaterials......Page 103
2.10.2 Superlenses......Page 106
Further Reading......Page 108
3 The Production of Colour by Reflection......Page 110
3.1.1 Reflection from a transparent plate......Page 111
3.2 Interference at a Single Thin Film in Air......Page 113
3.2.1 Reflection perpendicular to the film......Page 115
3.2.2 Variation with viewing angle......Page 116
3.2.3 Transmitted beams......Page 117
3.3 The Colour of a Single Thin Film in Air......Page 118
3.4 The Reflectivity of a Single Thin Film in Air......Page 120
3.5 The Colour of a Single Thin Film on a Substrate......Page 121
3.6 The Reflectivity of a Single Thin Film on a Substrate......Page 123
3.7.1 Antireflection coatings......Page 124
3.7.2 Antireflection layers......Page 125
3.7.3 Graded index antireflection coatings......Page 127
3.7.5 Interference-modulated (IMOD) displays......Page 129
3.8.1 Dielectric mirrors......Page 130
3.8.2 Multilayer stacks......Page 132
3.8.3 Interference filters and distributed Bragg reflectors......Page 133
3.9 Fibre Bragg Gratings......Page 134
3.10.1 Low-emissivity windows......Page 138
3.11 Photonic Engineering in Nature......Page 140
3.11.3 Labradorite......Page 141
3.11.4 Mirror eyes......Page 144
Appendix A3.1 The Colour of a Thin Film in White Light......Page 145
Further Reading......Page 146
4.1 Polarisation of Light......Page 148
4.2 Polarisation by Reflection......Page 150
4.3 Polars......Page 154
4.4 Crystal Symmetry and Refractive Index......Page 156
4.5.1 Double refraction......Page 157
4.5.2 Refractive index and crystal structure......Page 159
4.6.1 Uniaxial crystals......Page 162
4.6.2 Biaxial crystals......Page 163
4.7 Colour Produced by Polarisation and Birefringence......Page 166
4.8 Dichroism and Pleochroism......Page 168
4.9.1 Nonlinear crystals......Page 170
4.9.2 Second- and third-harmonic generation......Page 172
4.9.3 Frequency mixing......Page 174
4.9.4 Optical parametric amplifiers and oscillators......Page 175
4.10 Frequency Matching and Phase Matching......Page 176
4.11.2 Second-harmonic generation in glass......Page 179
4.11.3 Second-harmonic and sum-frequency-generation by organic materials......Page 180
4.12.1 The rotation of polarised light......Page 181
4.12.2 Circular birefringence and dichroism......Page 185
4.13.1 Liquid-crystal mesophases......Page 187
4.13.2 Liquid-crystal displays......Page 188
Further Reading......Page 192
5.1 Scattering and Extinction......Page 194
5.2 Tyndall Blue and Rayleigh Scattering......Page 195
5.3 Blue Skies, Red Sunsets......Page 197
5.4 Scattering and Polarisation......Page 200
5.5 Mie Scattering......Page 203
5.6 Blue Eyes, Blue Feathers and Blue Moons......Page 206
5.7 Paints, Sunscreens and Related Matters......Page 207
5.8 Multiple Scattering......Page 209
5.9 Gold Sols and Ruby Glass......Page 210
5.10 The Lycurgus Cup and Other Stained Glass......Page 212
Further Reading......Page 214
6 Colour Due to Diffraction......Page 216
6.1 Diffraction and Colour Production by a Slit......Page 217
6.2 Diffraction and Colour Production by a Rectangular Aperture......Page 219
6.3 Diffraction and Colour Production by a Circular Aperture......Page 221
6.4 The Diffraction Limit of Optical Instruments......Page 222
6.5 Colour Production by Linear Diffraction Gratings......Page 224
6.6 Two-Dimensional Gratings......Page 227
6.7 Estimation of the Wavelength of Light by Diffraction......Page 229
6.8.1 Bragg’s law......Page 230
6.8.2 Opals......Page 232
6.8.3 Artificial and inverse opals......Page 237
6.8.4 The effective refractive index of inverse opals......Page 240
6.8.5 Photonic crystals and photonic band gaps......Page 242
6.8.6 Dynamical form of Bragg’s law......Page 243
6.9.1 Random specks and droplets......Page 244
6.9.2 Colour from cholesteric liquid crystals......Page 247
6.9.3 Disordered two- and three-dimensional gratings......Page 249
6.10.1 Diffraction by moth-eye antireflection structures......Page 250
6.10.2 The cornea of the eye......Page 252
6.10.3 Some blue feathers......Page 253
6.11.2 Transmission holograms......Page 254
6.11.3 Reflection holograms......Page 256
6.11.4 Rainbow holograms......Page 258
6.11.5 Hologram recording media......Page 259
6.11.6 Embossed holograms......Page 261
Further Reading......Page 262
7.1 The Spectra of Atoms and Ions......Page 266
7.2 Terms and Levels......Page 271
7.3 Atomic Spectra and Chemical Analysis......Page 273
7.4 Fraunhofer Lines and Stellar Spectra......Page 274
7.5 Neon Signs and Early Plasma Displays......Page 275
7.6 The Helium–Neon Laser......Page 278
7.7 Sodium and Mercury Street Lights......Page 281
7.8 Transition Metals and Crystal-Field Colours......Page 283
7.9.1 Configurations and strong field energy levels......Page 289
7.9.2 Weak fields and term splitting......Page 290
7.9.3 Intermediate fields......Page 292
7.10 The Colour of Ruby......Page 296
7.11.1 The ruby laser: a three-level laser......Page 300
7.11.2 The titanium–sapphire laser......Page 301
7.12 Emerald, Alexandrite and Crystal-Field Strength......Page 302
7.13 Crystal-Field Colours in Minerals and Gemstones......Page 303
7.14 Colour as a Structural Probe......Page 306
7.15 Colours from Lanthanoid Ions......Page 307
7.16 The Neodymium (Nd3+) Solid-State Laser: A Four-Level Laser......Page 309
7.17 Amplification of Optical-Fibre Signals......Page 313
7.18 Transition Metal, Lanthanoid and Actinoid Pigments......Page 314
7.19 Spectral-Hole Formation......Page 316
A7.1.1 Electron configurations of the lighter atoms......Page 319
A7.1.3 The lanthanoid (rare earth) elements......Page 320
A7.2.1 The vector model of the atom......Page 321
A7.2.2 Energy levels and terms of many-electron atoms......Page 323
A7.2.4 Energy levels of many-electron atoms......Page 325
Further reading......Page 326
8.1 The Energy Levels of Molecules......Page 328
8.2 The Colours Arising in Some Simple Inorganic Molecules......Page 330
8.3 The Colour of Water......Page 334
8.4 Chromophores, Chromogens and Auxochromes......Page 335
8.5 Conjugated Bonds in Organic Molecules: The Carotenoids......Page 336
8.6 Conjugated Bonds Circling Metal Atoms: Porphyrins and Phthalocyanines......Page 338
8.7.1 Flavone-related colours: yellows......Page 342
8.7.2 Anthocyanin-related colours: reds and blues......Page 343
8.7.3 The colour of red wine......Page 347
8.8 Autumn Leaves......Page 351
8.9 Some Dyes and Pigments......Page 352
8.9.1 Indigo, Tyrian purple and mauve......Page 354
8.9.3 Melanins......Page 356
8.10.1 Charge-transfer processes......Page 359
8.10.2 Cation-to-cation (intervalence) charge transfer......Page 360
8.10.3 Anion-to-cation charge transfer......Page 364
8.10.4 Iron-containing minerals......Page 365
8.10.5 Intra-anion charge transfer......Page 367
8.11.1 The detection of metal ions......Page 368
8.11.2 Indicators......Page 369
8.11.3 Colorimetric sensor films and arrays......Page 372
8.11.4 Markers......Page 373
8.12 Dye Lasers......Page 374
8.13 Photochromic Organic Molecules......Page 377
Further Reading......Page 380
9.1 Luminescence......Page 382
9.2 Activators, Sensitisers and Fluorophores......Page 384
9.3.1 Energy absorption and emission......Page 387
9.3.2 Kinetic factors......Page 389
9.3.3 Quantum yield and reaction rates......Page 390
9.3.5 Quenching......Page 393
9.4.1 Halophosphate lamps......Page 398
9.4.2 Trichromatic lamps......Page 400
9.4.3 Other fluorescent lamps......Page 401
9.5 Plasma Displays......Page 402
9.6.1 Cathode rays......Page 404
9.6.2 Television tubes......Page 405
9.6.3 Other applications of cathodoluminescence......Page 408
9.7 Field-Emission Displays......Page 409
9.8 Phosphor Electroluminescent Displays......Page 410
9.9 Up-Conversion......Page 413
9.9.1 Ground-state absorption and excited-state absorption......Page 414
9.9.2 Energy transfer......Page 418
9.9.3 Other up-conversion processes......Page 420
9.10 Quantum Cutting......Page 421
9.11.1 Molecular fluorescence......Page 424
9.11.2 Fluorescent proteins......Page 426
9.11.3 Fluorescence microscopy......Page 428
9.11.4 Multiphoton excitation microscopy......Page 429
9.12 Fluorescent Nanoparticles......Page 430
9.13 Fluorescent Markers and Sensors......Page 431
9.14 Chemiluminescence and Bioluminescence......Page 432
9.16 Scintillators......Page 435
Further Reading......Page 437
10 Colour in Metals, Semiconductors and Insulators......Page 438
10.1 The Colours of Insulators......Page 439
10.2 Excitons......Page 440
10.4 Impurity Colours in Diamond......Page 443
10.5.1 The F centre......Page 448
10.5.2 Electron and hole centres......Page 449
10.5.4 Complex colour centres: laser action......Page 453
10.5.5 Photostimulable phosphors......Page 454
10.6.1 Coloured semiconductors......Page 455
10.6.2 Transparent conducting oxides......Page 456
10.7 The Colours of Semiconductor Alloys......Page 459
10.8.1 Direct and indirect band gaps......Page 460
10.8.2 Idealized diode structure......Page 462
10.8.3 High-brightness LEDs......Page 464
10.8.5 LED displays and white light generation......Page 465
10.9 Semiconductor Diode Lasers......Page 467
10.10.1 Nanostructures......Page 468
10.10.2 Quantum wells......Page 470
10.10.3 Quantum wires and quantum dots......Page 473
10.11.1 Molecular electroluminescence......Page 476
10.11.2 Organic light emitting diodes......Page 478
10.12 Electrochromic Films......Page 482
10.12.1 Tungsten trioxide electrochromic films......Page 484
10.12.2 Inorganic electrochromic materials......Page 486
10.12.4 Electrochromic polymers......Page 487
10.13.1 Photoconductivity and photovoltaic solar cells......Page 490
10.13.2 Dye-sensitised solar cells......Page 491
10.14.1 Charge coupled devices......Page 493
10.14.2 CCD photography......Page 495
10.15 The Colours of Metals......Page 496
10.16.1 Plasmons......Page 497
10.16.2 Surface plasmons and polaritons......Page 498
10.16.3 Polychromic glass......Page 500
10.16.4 Photochromic glass......Page 501
10.16.5 Photographic film......Page 503
10.16.6 Metal nanoparticle sensors and SERS......Page 505
10.17 Extraordinary Light Transmission and Plasmonic Crystals......Page 506
Further Reading......Page 507
Index......Page 510