Optics For Dummies

Introduction 1 About This Book 1 Conventions Used in This Book 2 What You’re Not to Read 3 Foolish Assumptions 3 How This Book Is Organized 3 Part I: Getting Up to Speed on Optics Fundamentals 4 Part II: Geometrical Optics: Working with More Than One Ray 4 Part III: Physical Optics: Using the Light Wave 4 Part IV: Optical Instrumentation: Putting Light to Practical Use 4 Part V: Hybrids: Exploring More Complicated Optical Systems 5 Part VI: More Than Just Images: Getting into Advanced Optics 5 Part VII: The Part of Tens 5 Icons Used in This Book 5 Where to Go from Here 6 Part I: Getting Up to Speed on Optics Fundamentals 7 Chapter 1: Introducing Optics, the Science of Light 9 Illuminating the Properties of Light 9 Creating images with the particle property of light 10 Harnessing interference and diffraction with the wave property of light 10 Using Optics to Your Advantage: Basic Applications 11 Expanding Your Understanding of Optics 12 Considering complicated applications 12 Adding advanced optics 13 Paving the Way: Contributions to Optics 13 Chapter 2: Brushing Up on Optics-Related Math and Physics 15 Working with Physical Measurements 15 Refreshing Your Mathematics Memory 16 Juggling variables with algebra 16 Finding lengths and angles with trigonometry 18 Exploring the unknown with basic matrix algebra 21 Reviewing Wave Physics 26 The wave function: Understanding its features and variables 26 Medium matters: Working with mechanical waves 28 Using wavefronts in optics 29 Chapter 3: A Little Light Study: Reviewing Light Basics 31 Developing Early Ideas about the Nature of Light 31 Pondering the particle theory of light 32 Walking through the wave theory of light 32 Taking a Closer Look at Light Waves 33 If light is a wave, what’s waving? Understanding electromagnetic radiation 33 Dealing with wavelengths and frequency: The electromagnetic spectrum 36 Calculating the intensity and power of light 36 Einstein’s Revolutionary Idea about Light: Quanta 37 Uncovering the photoelectric effect and the problem with light waves 38 Merging wave and particle properties: The photon 39 Let There Be Light: Understanding the Three Processes that Produce Light 40 Atomic transitions 40 Accelerated charged particles 41 Matter-antimatter annihilation 42 Introducing the Three Fields of Study within Optics 42 Geometrical optics: Studying light as a collection of rays 42 Physical optics: Exploring the wave property of light 43 Quantum optics: Investigating small numbers of photons 43 Chapter 4: Understanding How to Direct Where Light Goes 45 Reflection: Bouncing Light Off Surfaces 45 Determining light’s orientation 46 Understanding the role surface plays in specular and diffuse reflection 47 Appreciating the practical difference between reflection and scattering 48 Refraction: Bending Light as It Goes Through a Surface 50 Making light slow down: Determining the index of refraction 50 Calculating how much the refracted ray bends: Snell’s law 51 Bouncing light back with refraction: Total internal reflection 52 Varying the refractive index with dispersion 53 Birefringence: Working with two indices of refraction for the same wavelength 54 Diffraction: Bending Light around an Obstacle 55 Part II: Geometrical Optics: Working with More Than One Ray 57 Chapter 5: Forming Images with Multiple Rays of Light 59 The Simplest Method: Using Shadows to Create Images 60 Forming Images Without a Lens: The Pinhole Camera Principle 62 Eyeing Basic Image Characteristics for Optical System Design 63 The type of image created: Real or virtual 63 The orientation of the image relative to the object 63 The size of the image relative to the object 64 Zeroing In on the Focal Point and Focal Length 65 Determining the focal point and length 65 Differentiating real and virtual focal points 66 Chapter 6: Imaging with Mirrors: Bouncing Many Rays Around 69 Keeping it Simple with Flat Mirrors 69 Changing Shape with Concave and Convex Mirrors 70 Getting a handle on the mirror equation and sign conventions 71 Working with concave mirrors 72 Exploring convex mirrors 74 Chapter 7: Imaging with Refraction: Bending Many Rays at the Same Time 77 Locating the Image Produced by a Refracting Surface 78 Calculating where an image will appear 78 Solving single-surface imaging problems 80 Working with more than one refracting surface 83 Looking at Lenses: Two Refracting Surfaces Stuck Close Together 85 Designing a lens: The lens maker’s formula 85 Taking a closer look at convex and concave lenses 88 Finding the image location and characteristics for multiple lenses 89 D’oh, fuzzy again! Aberrations 91 Part III: Physical Optics: Using the Light Wave 95 Chapter 8: Optical Polarization: Describing the Wiggling Electric Field in Light 97 Describing Optical Polarization 97 Focusing on the electric field’s alignment 98 Polarization: Looking at the plane of the electric field 99 Examining the Different Types of Polarization 100 Linear, circular, or elliptical: Following the vector path 100 Random or unpolarized: Looking at changing or mixed states 107 Producing Polarized Light 108 Selective absorption: No passing unless you get in line 108 Scattering off small particles 109 Reflection: Aligning parallel to the surface 110 Birefringence: Splitting in two 111 Chapter 9: Changing Optical Polarization 113 Discovering Devices that Can Change Optical Polarization 113 Dichroic filters: Changing the axis with linear polarizers 114 Birefringent materials: Changing or rotating the polarization state 117 Rotating light with optically active materials 121 Jones Vectors: Calculating the Change in Polarization 121 Representing the polarization state with Jones vectors 121 Jones matrices: Showing how devices will change polarization 124 Matrix multiplication: Predicting how devices will affect incident light 126 Chapter 10: Calculating Reflected and Transmitted Light with Fresnel Equations 131 Determining the Amount of Reflected and Transmitted Light 131 Transverse modes: Describing the orientation of the fields 132 Defining the reflection and transmission coefficients 133 Using more powerful values: Reflectance and transmittance 134 The Fresnel equations: Finding how much incident light is reflected or transmitted 135 Surveying Special Situations Involving Reflection and the Fresnel Equations 136 Striking at Brewster’s angle 137 Reflectance at normal incidence: Coming in at 0 degrees 137 Reflectance at glancing incidence: Striking at 90 degrees 138 Exploring internal reflection and total internal reflection 138 Frustrated total internal reflection: Dealing with the evanescent wave 139 Chapter 11: Running Optical Interference: Not Always a Bad Thing 143 Describing Optical Interference 143 On the fringe: Looking at constructive and destructive interference 144 Noting the conditions required to see optical interference 145 Perusing Practical Interference Devices: Interferometers 146 Wavefront-splitting interferometers 146 Amplitude-splitting interferometers 151 Accounting for Other Amplitude-Splitting Arrangements 154 Thin film interference 154 Newton’s rings 157 Fabry-Perot interferometer 158 Chapter 12: Diffraction: Light’s Bending around Obstacles 161 From Near and Far: Understanding Two Types of Diffraction 162 Defining the types of diffraction 162 Determining which type of diffraction you see 163 Going the Distance: Special Cases of Fraunhofer Diffraction 164 Fraunhofer diffraction from a circular aperture 165 Fraunhofer diffraction from slits 167 Getting Close: Special Cases of Fresnel Diffraction 172 Fresnel diffraction from a rectangular aperture 173 Fresnel diffraction from a circular aperture 174 Fresnel diffraction from a solid disk 175 Diffraction from Fresnel zone plates 175 Part IV: Optical Instrumentation: Putting Light to Practical Use 179 Chapter 13: Lens Systems: Looking at Things the Way You Want to See Them 181 Your Most Important Optical System: The Human Eye 181 Understanding the structure of the human eye 182 Accommodation: Flexing some muscles to change the focus 183 Using Lens Systems to Correct Vision Problems 185 Corrective lenses: Looking at lens shape and optical power 185 Correcting nearsightedness, farsightedness, and astigmatism 186 Enhancing the Human Eye with Lens Systems 190 Magnifying glasses: Enlarging images with the simple magnifier 191 Seeing small objects with the compound microscope 192 Going the distance with the simple telescope 194 Jumping to the big screen: The optical projector 195 Chapter 14: Exploring Light Sources: Getting Light Where You Want It 197 Shedding Light on Common Household Bulbs 198 Popular bulb types and how they work 198 Reading electrical bulb rates 201 Shining More-Efficient Light on the Subject: Light Emitting Diodes 201 Looking inside an LED 202 Adding color with organic light emitting diodes 203 LEDs on display: Improving your picture with semiconductor laser diodes 204 Zeroing in on Lasers 205 Building a basic laser system 206 Comparing lasers to light bulbs 211 Chapter 15: Guiding Light From Here to Anywhere 213 Getting Light in the Guide and Keeping it There: Total Internal Reflection 213 Navigating numerical aperture: How much light can you put in? 214 Examining light guide modes 215 Categorizing Light Guide Types 216 Fiber-optic cables 216 Slab waveguides 220 Putting Light Guides to Work: Common Applications 221 Light pipes 221 Telecommunication links 221 Imaging bundles 224 Part V: Hybrids: Exploring More Complicated Optical Systems 227 Chapter 16: Photography: Keeping an Image Forever 229 Getting an Optical Snapshot of the Basic Camera 230 Lens: Determining what you see 231 Aperture: Working with f-number and lens speed 234 Shutter: Letting just enough light through 236 Recording media: Saving images forever 236 Holography: Seeing Depth in a Flat Surface 237 Seeing in three dimensions 237 Exploring two types of holograms 238 Relating the hologram and the diffraction grating 240 Graduating to 3-D Movies: Depth that Moves! 243 Circular polarization 243 Six-color anaglyph system 244 Shutter glasses 244 Chapter 17: Medical Imaging: Seeing What’s Inside You (No Knives Necessary!) 247 Shining Light into You and Seeing What Comes Out 247 X-rays 248 Optical coherence tomography 250 Endoscopes 251 Reading the Light that Comes Out of You 253 CAT scans 254 PET scans 255 NMR scans 256 MRI scans 257 Chapter 18: Optics Everywhere: Exploring Other Medical, Industrial, and Military Uses 259 Considering Typical Medical Procedures Involving Lasers 259 Removing stuff you don’t want: Tissue ablation 260 Sealing up holes or incisions 263 Purely cosmetic: Doing away with tattoos, varicose veins, and unwanted hair 264 Getting Industrial: Making and Checking Products Out with Optics 265 Monitoring quality control 265 Drilling holes or etching materials 265 Making life easier: Commercial applications 266 Applying Optics in Military and Law Enforcement Endeavors 267 Range finders 267 Target designation 268 Missile defense 268 Night vision systems 269 Thermal vision systems 270 Image processing 270 Chapter 19: Astronomical Applications: Using Telescopes 271 Understanding the Anatomy of a Telescope 272 Gathering the light 272 Viewing the image with an eyepiece 273 Revolutionizing Refracting Telescopes 274 Galilean telescope 275 Kepler’s enhancement 276 Reimagining Telescope Design: Reflecting Telescopes 277 Newtonian 277 Cassegrain 278 Gregorian 279 Hybrid Telescopes: Lenses and Mirrors Working Together 280 Schmidt 280 Maksutov 281 Invisible Astronomy: Looking Beyond the Visible 282 When One Telescope Just Won’t Do: The Interferometer 283 Part VI: More Than Just Images: Getting into Advanced Optics 285 Chapter 20: Index of Refraction, Part 2: You Can Change It! 287 Electro-Optics: Manipulating the Index of Refraction with Electric Fields 287 Dielectric polarization: Understanding the source of the electro-optic effect 288 Linear and quadratic: Looking at the types of electro-optic effects 289 Examining electro-optic devices 293 Acousto-Optics: Changing a Crystal’s Density with Sound 295 The acousto-optic effect: Making a variable diffraction grating 295 Using acousto-optic devices 296 Frequency Conversion: Affecting Light Frequency with Light 297 Second harmonic generation: Doubling the frequency 297 Parametric amplification: Converting a pump beam into a signal beam 298 Sum and difference frequency mixing: Creating long or short wavelengths 299 Chapter 21: Quantum Optics: Finding the Photon 301 Weaving Together Wave and Particle Properties 301 Seeing wave and particle properties of light 302 Looking at wave and particle properties of matter 304 Experimental Evidence: Observing the Dual Nature of Light and Matter 306 Young’s two-slit experiment, revisited 306 Diffraction of light and matter 307 The Mach-Zehnder interferometer 308 Quantum Entanglement: Looking at Linked Photons 308 Spooky action: Observing interacting photons 308 Encryption and computers: Developing technology with linked photons 309 Part VII: The Part of Tens 311 Chapter 22: Ten Experiments You Can Do Without a $1-Million Optics Lab 313 Chromatic Dispersion with Water Spray 313 The Simple Magnifier 314 Microscope with a Marble 314 Focal Length of a Positive Lens with a Magnifying Glass 314 Telescope with Magnifying Glasses 315 Thin Film Interference by Blowing Bubbles 316 Polarized Sunglasses and the Sky 316 Mirages on a Clear Day 317 Spherical Aberration with a Magnifying Glass 317 Chromatic Aberration with a Magnifying Glass 318 Chapter 23: Ten Major Optics Discoveries — and the People Who Made them Possible 319 The Telescope (1610) 319 Optical Physics (Late 1600s) 320 Diffraction and the Wave Theory of Light (Late 1600s) 320 Two-Slit Experiment (Early 1800s) 321 Polarization (Early 1800s) 321 Rayleigh Scattering (Late 1800s) 321 Electromagnetics (1861) 322 Electro-Optics (1875 and 1893) 322 Photon Theory of Light (1905) 322 The Maser (1953) and The Laser (1960) 323 Index 325