Preface to the Fourth Edition ................................ xiii
Symbols and Abbreviations ...................................... xv
1 Introduction ................................................. 1
1.1 Early History ........................................... 1
1.2 Thin-Film Filters ....................................... 5
References .................................................. 10
2 Basic Theory ................................................ 13
2.1 Maxwell's Equations and Plane Electromagnetic Waves .... 13
2.1.1 The Poynting Vector ............................. 18
2.2 The Simple Boundary .................................... 21
2.2.1 Normal Incidence ................................ 23
2.2.2 Oblique Incidence ............................... 27
2.2.2.1 p-Polarized Light ...................... 28
2.2.2.2 s-Polarized Light ...................... 30
2.2.3 The Optical Admittance for Oblique Incidence .... 31
2.2.4 Normal Incidence in Absorbing Media ............. 33
2.2.5 Oblique Incidence in Absorbing Media ............ 38
2.3 The Reflectance of a Thin Film ......................... 42
2.4 The Reflectance of an Assembly of Thin Films ........... 45
2.5 Reflectance, Transmittance, and Absorptance ............ 48
2.6 Units .................................................. 51
2.7 Summary of Important Results ........................... 52
2.8 Potential Transmittance ................................ 57
2.9 A Theorem on the Transmittance of a Thin-Film
Assembly ............................................... 60
2.10 Coherence .............................................. 61
2.11 Incoherent Reflection at Two or More Surfaces .......... 66
References .................................................. 71
3 Theoretical Techniques ...................................... 73
3.1 Quarter- and Half-Wave Optical Thicknesses ............. 73
3.2 Admittance Loci ........................................ 74
3.3 Electric Field and Losses in the Admittance Diagram .... 80
3.4 The Vector Method ...................................... 87
3.5 The Herpin Index ....................................... 89
3.6 Alternative Method of Calculation ...................... 89
3.7 Smith's Method of Multilayer Design .................... 92
3.8 The Smith Chart ........................................ 95
3.9 Reflection Circle Diagrams ............................. 97
References ................................................. 103
4 Antireflection Coatings .................................... 105
4.1 Antireflection Coatings on High-Index Substrates ...... 106
4.1.1 The Single-Layer Antireflection Coating ........ 106
4.1.2 Double-Layer Antireflection Coatings ........... 112
4.1.3 Multilayer Coatings ............................ 121
4.2 Antireflection Coatings on Low-Index Substrates ....... 129
4.2.1 The Single-Layer Antireflection Coating ........ 130
4.2.2 Two-Layer Antireflection Coatings .............. 130
4.2.3 Multilayer Antireflection Coatings ............. 140
4.3 Equivalent Layers ..................................... 156
4.4 Antireflection Coatings for Two Zeros ................. 168
4.5 Antireflection Coatings for the Visible and the
Infrared .............................................. 172
4.6 Inhomogeneous Layers .................................. 179
4.7 Further Information ................................... 182
References ................................................. 183
5 Neutral Mirrors and Beam Splitters ......................... 185
5.1 High-Reflectance Mirror Coatings ...................... 185
5.1.1 Metallic Layers ................................ 185
5.1.2 Protection of Metal Films ...................... 187
5.1.3 Overall System Performance, Enhanced
Reflectance .................................... 193
5.1.4 Reflecting Coatings for the Ultraviolet ........ 196
5.2 Neutral Beam Splitters ................................ 198
5.2.1 Beam Splitters Using Metallic Layers ........... 198
5.2.2 Beam Splitters Using Dielectric Layers ......... 201
5.3 Neutral-Density Filters ............................... 205
References ................................................. 207
6 Multilayer High-Reflectance Coatings ....................... 209
6.1 The Fabry-Perot Interferometer ........................ 209
6.2 Multilayer Dielectric Coatings ........................ 215
6.2.1 All-Dielectric Multilayers with Extended
High-Reflectance Zones ......................... 225
6.2.2 Coating Uniformity Requirements ................ 230
6.3 Losses ................................................ 234
References ................................................. 238
7 Edge Filters ............................................... 241
7.1 Thin-Film Absorption Filters .......................... 241
7.2 Interference Edge Filters ............................. 242
7.2.1 The Quarter-Wave Stack ......................... 243
7.2.2 Symmetrical Multilayers and the Herpin Index ... 244
7.2.2.1 Application of the Herpin Index to
the Quarter-Wave Stack ................ 248
7.2.2.2 Application of the Herpin Index to
Multilayers of Other Than Quarter-
Waves ................................. 253
7.2.3 Performance Calculations ....................... 256
7.2.3.1 Transmission at the Edge of a Stop
Band .................................. 256
7.2.3.2 Transmission in the Center of a Stop
Band .................................. 258
7.2.3.3 Transmission in the Pass Band ......... 260
7.2.3.4 Reduction of Pass-Band Ripple ......... 262
7.2.3.5 Summary of Design Procedure so Far .... 265
7.2.3.6 More Advanced Procedures for
Eliminating Ripple .................... 266
7.2.3.7 Practical Filters ..................... 281
7.2.3.8 Extending the Rejection Zone by
Interference Methods .................. 283
7.2.3.9 Extending the Transmission Zone ....... 287
7.2.3.10 Reducing the Transmission Zone ........ 295
7.2.3.11 Edge Steepness ........................ 296
References ................................................. 297
8 Band-Pass Filters .......................................... 299
8.1 Broadband-Pass Filters ................................ 299
8.2 Narrowband Filters .................................... 302
8.2.1 The Metal-Dielectric Single-Cavity Filter ...... 302
8.2.2 The All-Dielectric Single-Cavity Filter ........ 310
8.2.2.1 Case 1: Even Number (2x) of Layers .... 313
8.2.2.2 Case II: Odd Number (2x + 1) of
Layers ................................ 315
8.2.2.3 Phase Shift: Case 1 ................... 316
8.2.2.4 Phase Shift: Case II .................. 317
8.2.3 The Solid Etalon Filter ........................ 325
8.2.4 The Effect of Varying the Angle of Incidence ... 329
8.2.4.1 Simple Tilts in Collimated Light ...... 329
8.2.4.2 Case I: High-Index Cavities ........... 332
8.2.4.3 Case II: Low-Index Cavities ........... 333
8.2.4.4 Effect of an Incident Cone of Light ... 335
8.2.5 Sideband Blocking .............................. 341
8.3 Multiple Cavity Filters ............................... 342
8.3.1 Thelen's Method of Analysis .................... 349
8.4 Higher Performance in Multiple-Cavity Filters ......... 356
8.4.1 Effect of Tilting .............................. 364
8.4.2 Losses in Multiple Cavity Filters .............. 367
8.4.2.1 Case I: High-Index Cavities ........... 368
8.4.2.2 Case II: Low-Index Cavities ........... 369
8.4.3 Further Information ............................ 369
8.5 Phase Dispersion Filter ............................... 370
8.6 Multiple Cavity Metal-Dielectric Filters .............. 377
8.6.1 The Induced-Transmission Filter ................ 380
8.6.1.1 Potential Transmittance ............... 381
8.6.1.2 Optimum Exit Admittance ............... 382
8.6.1.3 Maximum Potential Transmittance ....... 384
8.6.1.4 Matching Stack ........................ 384
8.6.1.5 Front Surface Equivalent Admittance ... 386
8.6.2 Examples of Filter Designs ..................... 386
8.7 Measured Filter Performance ........................... 396
References ................................................. 399
9 Tilted Coatings ............................................ 403
9.1 Modified Admittances and the Tilted Admittance
Diagram ............................................... 403
9.2 Application of the Admittance Diagram ................. 411
9.3 Polarizers ............................................ 425
9.3.1 The Brewster Angle Polarizing Beam Splitter .... 425
9.3.2 Plate Polarizer ................................ 430
9.3.3 Cube Polarizers ................................ 431
9.4 Nonpolarizing Coatings ................................ 431
9.4.1 Edge Filters at Intermediate Angle of
Incidence ...................................... 432
9.4.2 Reflecting Coatings at Very High Angles of
Incidence ...................................... 437
9.4.3 Edge Filters at Very High Angles of
Incidence ...................................... 441
9.5 Antireflection Coatings ............................... 442
9.5.1 p-Polarization Only ............................ 442
9.5.2 s-Polarization Only ............................ 443
9.5.3 s- and p-Polarization Together ................. 444
9.6 Retarders ............................................. 447
9.6.1 The Ellipsometric Parameters and Relative
Retardation .................................... 447
9.6.2 Series of Coated Surfaces ...................... 448
9.6.3 Retarders ...................................... 449
9.6.4 Simple Retarders ............................... 451
9.6.5 Multilayer Retarders at One Wavelength ......... 455
9.6.6 Multilayer Retarders for a Range of
Wavelengths .................................... 459
9.7 Optical Tunnel Filters ................................ 464
References ................................................. 467
10 Color in Optical Coatings .................................. 471
10.1 Color Definition ...................................... 471
10.2 The 1964 Supplementary Colorimetric Observer .......... 478
10.3 Metamerism ............................................ 479
10.4 Other Color Spaces .................................... 480
10.5 Hue and Chroma ........................................ 481
10.6 Brightness and Optimal Stimuli ........................ 482
10.7 Colored Fringes ....................................... 485
References ................................................. 487
11 Production Methods and Thin-Film Materials ................. 489
11.1 The Production of Thin Films .......................... 490
11.1.1 Thermal Evaporation ............................ 491
11.1.2 Energetic Processes ............................ 501
11.1.3 Other Processes ................................ 513
11.1.4 Baking ......................................... 517
11.2 Measurement of the Optical Properties ................. 520
11.3 Measurement of the Mechanical Properties .............. 540
11.4 Toxicity .............................................. 550
11.5 Summary of Some Properties of Common Materials ........ 551
References ................................................. 561
12 Factors Affecting Layer and Coating Properties ............. 569
12.1 Microstructure and Thin-Film Behavior ................. 569
12.2 Sensitivity to Contamination .......................... 584
References ................................................. 592
13 Layer Uniformity and Thickness Monitoring .................. 595
13.1 Uniformity ............................................ 595
13.1.1 Flat Plate ..................................... 597
13.1.2 Spherical Surface .............................. 598
13.1.3 Rotating Substrates ............................ 598
13.1.4 Use of Masks ................................... 603
13.2 Substrate Preparation ................................. 604
13.3 Thickness Monitoring and Control ...................... 607
13.3.1 Optical Monitoring Techniques ................. 608
13.3.2 The Quartz-Crystal Monitor .................... 618
13.3.3 Monitoring by Deposition Time ................. 620
13.4 Tolerances ............................................ 621
References ................................................. 636
14 Specification of Filters and Environmental Effects ......... 641
14.1 Optical Properties .................................... 641
14.1.1 Performance Specification ...................... 641
14.1.2 Manufacturing Specification .................... 644
14.1.3 Test Specification ............................. 644
14.2 Physical Properties ................................... 648
14.2.1 Abrasion Resistance ............................ 648
14.2.2 Adhesion ....................................... 651
14.2.3 Environmental Resistance ....................... 652
References ................................................. 653
15 System Considerations: Applications of Filters and
Coatings ................................................... 655
15.1 Potential Energy Grasp of Interference Filters ........ 659
15.2 Narrowband Filters in Astronomy ....................... 665
15.3 Atmospheric Temperature Sounding ...................... 670
15.4 Order Sorting Filters for Grating Spectrometers ....... 679
15.5 Glare Suppression Filters and Coatings ................ 691
15.6 Some Coatings Involving Metal Layers .................. 695
15.6.1 Electrode Films for Schottky-Barrier
Photodiodes .................................... 695
15.6.2 Spectrally Selective Coatings for
Photothermal Solar Energy Conversion ........... 698
15.6.3 Heat Reflecting Metal-Dielectric Coatings ...... 703
References ................................................. 705
16 Other Topics ............................................... 707
16.1 Rugate Filters ........................................ 707
16.2 Ultrafast Coatings .................................... 718
16.3 Automatic Methods ..................................... 729
16.4 Gain in Optical Coatings .............................. 740
16.4.1 Oblique Incidence ............................. 744
16.5 Photonic Crystals ..................................... 748
16.5.1 What Is a Photonic Crystal? .................... 750
16.5.2 Two-Dimensional Photonic Crystals .............. 750
16.5.3 One-Dimensional Photonic Crystals .............. 751
References ................................................. 756
17 Characteristics of Thin-Film Dielectric Materials .......... 759
References ................................................. 766
Bibliography .................................................. 771
Index ......................................................... 773
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