Foreword xi
Preface xiii
Dedications and Acknowledgements xvii
About the Companion Website xix
1 What is a Hologram? 1
1.1 Introduction 1
1.2 Gabor’s Invention of Holography 1
1.3 The Work of Lippmann 5
1.4 Amplitude and Phase Holograms 5
1.5 Transmission Holograms 6
1.6 Reflection Holograms 7
1.7 Edge-lit Holograms 9
1.8 “Fresnel” and “Fraunhofer” Holograms 10
1.9 Display Holograms 12
1.10 Security Holograms 15
1.11 What is Not a Hologram? 16
1.11.1 Dot-matrix Holograms 17
1.11.2 Other Digital Image Types 18
1.11.3 Holographic Optical Element (HOE) 18
1.11.4 Pepper’s Ghost 18
1.11.5 Anaglyph Method 20
1.11.6 Lenticular Images 21
1.11.7 Scrambled Indicia 22
1.11.8 Hand-drawn “Holograms” 23
1.11.9 “Magic Eye” 24
Notes 25
2 Important Optical Principles and their Occurrence in Nature 27
2.1 Background 27
2.2 The Wave/Particle Duality of Light 29
2.3 Wavelength 30
2.4 Representation of the Behaviour of Light 32
2.4.1 A Ray of Light 32
2.4.2 A Wave Front 32
2.5 The Laws of Reflection 32
2.6 Refraction 34
2.7 Refractive Index 34
2.7.1 Refractive Index of Relevant Materials 34
2.8 Huygens’ Principle 34
2.9 The Huygens–Fresnel Principle 35
2.10 Snells Law 36
2.11 Brewster’s Law 38
2.12 The Critical Angle 40
2.13 TIR in Optical Fibres 42
2.14 Dispersion 42
2.15 Diffraction and Interference 43
2.16 Diffraction Gratings 45
2.17 The Grating Equation 45
2.18 Bragg’s Law 47
2.19 The Bragg Equation for the Recording of a Volume Hologram 50
2.20 The Bragg Condition in Lippmann Holograms 52
2.21 The Practical Preparation of Holograms 54
Notes 54
3 Conventional Holography and Lasers 55
3.1 Historical Aspect 55
3.2 Choosing a Laser for Holography 56
3.3 Testing a Candidate Laser 58
3.4 The Race for the Laser 59
3.5 Light Amplification by Stimulated Emission of Radiation (LASER) 60
3.6 The Ruby Laser 61
3.7 Laser Beam Quality 63
3.8 Photopic and Scotopic Response of the Human Eye 65
3.9 Eye Safety I 65
3.10 The Helium–Neon Laser 66
3.11 TheInert Gas Ion Lasers 68
3.12 Helium–Cadmium Lasers 69
3.13 Diode]pumped Solid]state Lasers 70
3.14 Fibre Lasers – A Personal Lament! 71
3.15 Eye Safety II 72
3.16 The Efficiency Revolution in Laser Technology 73
3.17 Laser Coherence 73
Notes 75
4 Digital Image Holograms 77
4.1 Why is There Such Desire to Introduce Digital Imaging into Holography? 77
4.2 The Kinegram 78
4.3 E]beam Lithographic Gratings 80
4.4 Grading Security Features 81
4.5 The Common “Dot]matrix” Technique 83
4.6 Case History: Pepsi Cola 88
4.7 Other Direct Methods of Producing Digital Holograms 88
4.8 Simian – The Ken Haines Approach to Digital Holograms 90
4.9 Zebra Reflection Holograms 90
Notes 92
5 Recording Materials for Holography 93
5.1 Silver Halide Recording Materials 93
5.2 Preparation of Silver Bromide Crystals 94
5.3 The Miraculous Photographic Application of Gelatin 95
5.4 Why Has it Taken so Long to Arrive at Today’s Excellent Standard of Recording Materials for Holography? 96
5.5 Controlled Growth Emulsions 97
5.6 Unique Requirements of Holographic Emulsions 100
5.7 Which Parameters Control Emulsion Speed? 101
5.8 Sensitisation 103
5.8.1 Chemical Sensitisation 103
5.8.2 Spectral Sensitisation 103
5.9 Developer Restrictions 104
5.10 The Coated Layer 105
5.11 The Non]typical Use of Silver Halides for Holography 106
5.12 Photopolymer 108
5.13 Photoresist 111
5.14 Dichromated Gelatin 112
5.14.1 Principle of Operation of DCG 113
5.14.2 Practical Experimentation with DCG 113
5.15 Photo]thermoplastics 114
Notes 115
6 Processing Techniques 117
6.1 Processing Chemistry for Silver Halide Materials 117
6.2 Pre]treatment of Emulsion 120
6.3 “Pseudo]colour” Holography 121
6.4 How Does Triethanolamine Treatment Work? 122
6.5 Wetting Emulsion Prior to Development 123
6.6 Development 124
6.7 Filamental and Globular Silver Grains 125
6.8 The H&D Curve 126
6.9 Chemical Development Mechanism 129
6.10 Pyro Developer Formulation 131
6.11 Ascorbic Acid Developers 131
6.11.1 Ascorbic Acid Developer Formulation 132
6.12 “Stop” Bath 133
6.12.1 “Stop” Bath Formulation 133
6.13 Fixing 134
6.13.1 Fixer Bath Formulation 135
6.14 Bleaching Solutions 135
6.15 Re]halogenating Bleaches 139
6.15.1 Ferric Re]halogenating Bleach Formulation 141
6.15.2 Cupric Re]halogenating Bleach Formulation 142
6.15.3 Re]halogenating Bleaching in Coarse]grain Emulsions such as “Holotest” 143
6.15.4 Re]halogenating Bleach Formulations for Coarse]grain Recording Materials 144
6.16 Post]process Conditioning Baths 144
6.17 Silver Halide Sensitised Gelatin (SHSG) 146
6.18 Surface]relief Effects by Etching Bleaches 147
6.18.1 Kodak EB4 Formulation 147
6.19 Photoresist Development Technique 148
Notes 150
7 Infrastructure of a Holography Studio and its
Principal Components 153
7.1 Setting Up a Studio 153
7.2 Ground Vibration 154
7.3 Air Movement 155
7.4 Local Temperature Change 156
7.5 Safe Lighting 156
7.6 Organising Your Chemistry Laboratory 159
7.7 The Optical Table: Setting Up the Vital Components 159
7.8 Spatial Filtration 160
7.8.1 Mode of Operation of a Spatial Filter 160
7.8.2 Setting Up a Spatial Filter 161
7.8.3 Selection of Pinhole Diameter 163
7.8.4 Aligning the Spatial Filter in the Laser Beam 163
7.8.5 Centring the Pinhole 164
7.9 Filtering a “White” Laser Beam 166
7.10 Collimators 167
7.10.1 Mirror Collimators 168
7.10.2 Lens Collimation 171
7.10.3 Establishing the Approximate Focal Length of a Collimator 172
7.10.4 Finding the Precise Focal Point of a Collimator 172
7.10.5 Plano]convex Lens Alignment 173
7.10.6 Spherical Mirror Collimator Alignment 174
7.11 Organising Suitable Plate Holders for Holography 174
7.12 Hot Glue – The Holographer’s Disreputable Friend 175
7.13 Mirror Surfaces 176
7.13.1 Dielectric Mirrors 177
7.13.2 Metallic Coatings 177
7.14 Beam Splitters 178
7.14.1 Metallised Beam Splitters 179
7.14.2 Dielectric Beam Splitters 180
7.15 Shutters 181
7.16 Fringe Lockers 181
7.17 Optics Stands 182
7.18 Safety – Reprise 182
Notes 183
8 Making Conventional Denisyuk, Transmission and Reflection Holograms in the Studio 185
8.1 Introduction 185
8.2 The Denisyuk Configuration 186
8.3 The Realism of Denisyuk Holograms 186
8.4 The Limitations of Denisyuk Holograms 187
8.5 The Denisyuk Set]up 188
8.6 “Recording Efficiency” 189
8.7 Diffraction Efficiency 191
8.8 Spectrum of the Viewing Illumination 192
8.9 Other Factors Influencing Apparent Hologram Brightness 194
8.10 Problems Faced in the Production of High]quality Holograms 196
8.11 Selecting a Reference Angle 198
8.12 Index]matching Safety 200
8.13 Vacuum Chuck Method to Hold Film During Exposure 200
8.14 Setting the Plane of Polarisation 201
8.15 Full]colour “Denisyuk” Holograms 203
8.16 Perfect Alignment of Multiple Laser Beams 204
8.17 “Burn Out” 208
8.18 Hybrid (Boosted) Denisyuks 209
8.19 Contact
Copying 211
8.20 The Rainbow Hologram Invention 212
8.21 A Laser Transmission Master Hologram 213
8.22 Laser Coherence Length 215
8.23 The Second Generation H2 Transmission Rainbow (Benton) Hologram 217
8.24 Developments of the Rainbow Hologram Technique 222
8.25 Using the α]Angle Theory to Produce Better Colour Rainbow Images 225
8.26 Aligning the Master Hologram with the α]Angle 228
8.27 Producing an α]Angle H2 Transfer 231
8.28 Utilising the Full Gamut of Rainbow Colours 232
8.29 Reflection Hologram Transfers 232
8.30 “Pseudo]colour” Holograms 235
8.31 Real]colour Holograms 237
Notes 237
9 Sources of Holographic Imagery 239
9.1 The Methods for Incorporation of 3D Artwork into Holograms 239
9.2 Making Holograms of Models and Real Objects 239
9.3 Models Designed for Multi]colour Rainbow Holograms 240
9.4 Supporting the Model 240
9.5 Pulse Laser Origination 242
9.6 The“2D/3D” Technique 244
9.7 The Rationale Behind Holographic Stereograms 246
9.8 Various Configurations for Holographic Stereograms 249
9.9 The Embossed Holographic Stereogram 250
9.10 Stereographic Film Recording Configuration 252
9.11 Shear Camera Recording 253
9.12 The Number of Image Channels for a Holographic Stereogram 256
9.13 Process Colours and Holography – An Uncomfortable Partnership 257
9.14 Assimilating CMYK Artwork with Holography 260
9.15 Interpretation of CMYK Separations in the RGB Format 261
Notes 262
10 A Personal View of the History of Holography 263
Notes 293
Epilogue: An Overview of the Impact of Holography in the
World of Imaging 295
Notes 301
Index 303
