Optical System Design

Chapter 1. Basic Optics and Optical System Specifications 1 The Purpose of an Imaging Optical System 1 How to Specify Your Optical System: Basic Parameters 4 Basic Definition of Terms 11 Useful First-Order Relationships 15 Chapter 2. Stops and Pupils and Other Basic Principles 29 The Role of the Aperture Stop 29 Entrance and Exit Pupils 31 Vignetting 32 Chapter 3. Diffraction, Aberrations, and Image Quality 35 What Image Quality Is All About 35 What Are Geometrical Aberrations and Where Do They Come From? 36 What Is Diffraction? 40 Diffraction-Limited Performance 43 Derivation of System Specifications 45 Chapter 4. The Concept of Optical Path Difference 49 Optical Path Difference (OPD) and the Rayleigh Criteria 49 Peak-to-Valley and RMS Wavefront Error 52 The Wave Aberration Polynomial 55 Depth of Focus 56 Chapter 5. Review of Specific Geometrical Aberrations and How to Get Rid of Them 59 Spherical Aberration 60 Coma 72 Astigmatism 75 For more information about this title, click here vi Contents Field Curvature and the Role of Field Lenses 78 Distortion 85 Axial Color 89 Lateral Color 90 Parametric Analysis of Aberrations Introduced by Plane Parallel Plates 91 Chapter 6. Glass Selection (Including Plastics) 95 Material Properties Overview 95 The Glass Map and Partial Dispersion 96 Parametric Examples of Glass Selection 102 How to Select Glass 106 Plastic Optical Materials 109 A Visual Aid to Glass Selection 111 Chapter 7. Spherical and Aspheric Surfaces 115 Definition of an Aspheric Surface 115 Conic Surfaces 117 Application of Aspheric Surfaces in Reflective and Refractive Systems 119 Guidelines in the Use of Aspheric Surfaces 124 Specification of Aspheric Surfaces 126 Chapter 8. Design Forms 129 Introduction 129 System Configurations for Refractive Systems 131 System Configurations for Reflective Systems 138 Reflective Systems, Relative Merits 144 Refractive Systems, Relative Merits 146 Mirrors and Prisms 147 Design of Visual Systems 155 Chapter 9. The Optical Design Process 167 What Do We Do When We Optimize a Lens System? 168 How Does the Designer Approach the Optical Design Task? 171 Sample Lens Design Problem 176 Contents vii Chapter 10. Computer Performance Evaluation 179 What Is Meant by Performance Evaluation 179 What Is Resolution? 180 Ray Trace Curves 181 Spot Diagrams 187 Optical Path Difference 189 Encircled Energy 189 MTF 191 Chapter 11. Gaussian Beam Imagery 199 Beam Waist and Beam Divergence 201 Collimation of Laser Beams 203 Propagation of Gaussian Beams and Focusing into a Small Spot 204 Truncation of a Gaussian Beam 205 Application of Gaussian Beam Optics in Laser Systems 208 F-θ Lenses in Laser Scanners 211 Chapter 12. Basics of Thermal Infrared Imaging in the 3- to 5- and 8- to 12-μm Spectral Bands (Plus UV Optics) 213 The Basics of Thermal Infrared Imaging 213 The Dewar, Cold Stop, and Cold Shield 217 Cold Stop Efficiency 219 Scanning Methods 222 IR Materials 229 Reduced Aberrations with IR Materials 236 Image Anomalies 239 Athermalization 246 System Design Examples 250 Optical Systems for the UV 255 Chapter 13. Diffractive Optics 259 Introduction 259 The Many Faces of Diffractive Optics 262 What Design and Modeling Tools Should I Use? 277 How Are Diffractives Fabricated? 287 Where Are Diffractives Used? 308 References 318 viii Contents Chapter 14. Design of Illumination Systems 321 Introduction 321 Köhler and Abbe Illumination 322 Optical Invariant and Etendue 324 Other Types of Illumination Systems 329 Chapter 15. Performance Evaluation and Optical Testing 333 Testing with the Standard 1951 U.S. Air Force Target 333 The Modulation Transfer Function 337 Interferometry 340 Other Tests 344 Chapter 16. Tolerancing and Producibility 347 Introduction 347 What Are Testplates and Why Are They Important? 348 How to Tolerance an Optical System 353 How Image Degradations from Different Tolerances Are Summed 356 Forms of Tolerances 359 Adjusting Parameters 364 Typical Tolerances for Various Cost Models 366 Example of Tolerance Analysis 367 Surface Irregularities 374 How Does Correlation Relate to Performance? 376 Effect to Spot Diameter 377 Effect to MTF: The Optical Quality Factor 379 Beam Diameter and Surface Irregularity 383 The Final Results 384 Chapter 17. Optomechanical Design 389 Environmental Considerations 389 Applicable Design Guidelines 393 Environmental Testing Methods 393 Mechanical Parameters and Properties 393 Typical Mechanical Property Values for Selected Materials 394 Structural Design 396 Vibration, Self-Weight Deflection, and Fundamental Frequency 398 Shock 400 Contents ix Rigid Housing Configurations 400 Modular Construction 401 Support Structure Configurations 405 Establishing Axial and Lateral Preload Requirements 414 Spherical and Crowned Lens Rims 415 Interfaces for Other Optical Components 416 Individual Lens Mounting Techniques 419 Surface Contact Interface Shapes 426 Mounting Windows, Shells, and Domes 429 Stress Consequences of Axial Preload 434 Temperature Effects on Axial Preload 436 Radial Stresses and Their Variations with Temperature 439 Bending Effects in Rotationally Symmetric Optics 439 Multiple-Component Lens Assemblies 441 Incorporating Prisms into the Design 452 Mirror Mountings 459 Mechanical Athermalization Techniques 467 References 476 Chapter 18. Optical Manufacturing Considerations 479 Material 480 Manufacturing 485 Special Fabrication Considerations 492 Relative Manufacturing Cost 502 Sourcing Considerations 502 Conclusion 504 Chapter 19. Polarization Issues in Optical Design 507 Introduction 507 Introduction to Polarization 508 The Mathematical Description of Polarized Light 513 Some Polarization Phenomena 523 Polarization Control Nuts and Bolts 535 Polarization Analysis of an Optical System 555 Minimizing Polarization Problems in Optical Design 559 Polarization as a Tool in Optical System Design 560 Summary 565 Bibliography 567 x Contents Chapter 20. Optical Thin Films 569 Introduction 569 Designing Optical Coatings 570 Various Categories of Optical Coatings 571 Optical Coating Process 578 Coating Performance Versus Number of Layers 582 Specifying Coating Requirements 583 Relationship Between Production Cost, Tolerances, and Quality 584 Bibliography 585 Chapter 21. Hardware Design Issues 587 Off-the-Shelf Optics 587 How to Effectively Work with Off-the-Shelf Optics 589 Working with Off-the-Shelf Singlets and Doublets 590 Example of Lens Used at Conjugates Different from What It Was Designed 591 Pupil Matching 594 Development of a Lab Mockup Using Off-the-Shelf Optics 595 Stray Light Control 595 Optomechanical Design 600 Chapter 22. Lens Design Optimization Case Studies 603 Error Function Construction 603 Achromatic Doublet Lens Design 605 Double Gauss Lens Design 610 Digital Camera Lens 632 Binocular Design 642 Parametric Design Study of Simple Lenses Using Advanced Manufacturing Methods 646 Design Data for Double Gauss 655 Chapter 23. Optical Sensor Systems Modeling and Analysis 659 Introduction 659 Image Formation 660 Detector Arrays 663 Optical System Noise Characteristics 669 Contents xi Color Sensors 691 Electronic Correction 696 Camera Connectivity 697 Bibliography 701 Chapter 24. Stray Light and Optical Scattering 703 Introduction 703 Stray Light Scatter Sources 703 Types of Scatter 711 Modeling and Analysis Techniques 713 Veiling Glare 715 Cleanliness 716 Suppression Techniques 717 Bright Field and Dark Field 731 How to Avoid Unwanted Stray Light 736 Bibliography 737 Chapter 25. Bloopers and Blunders in Optics 739 Distortion in a 1:1 Imaging Lens 739 Zoom Periscope 740 Sign of Distortion 742 Lens Elements That Are Not Necessary 744 Pupil Problems 744 Not Enough Light 745 Athermalization Using Teflon 746 Athermalization Specifications 746 Bad Glass Choice 747 Elements in Backward 747 Insufficient Sampling of Fields of View or Aperture 748 Images Upside Down or Rotated 749 The Hubble Telescope Null Lens Problem 750 Wrong Glass Type in a Precision Lens System 755 Single Use Camera with a Diffractive Achromat 755 Wrong Image Handedness 756 Cemented Triplet as Part of an Imaging System 757 Total Internal Reflection in a Cube Beamsplitter 758 Diffractive Optics Issues 760 Case of the Miscoated Mangin 763 Telescopes and Polarization 765 xii Contents Chapter 26. Rule of Thumb and Hints 767 General Optical Design Topics 767 Optomechanical Topics 770 Diffractive Optics 772