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This section contains the introduction to the series, the preface, the table of contents, and the glossary of symbols. |
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Library of Congress Cataloging-in-Publication Data Daniels, Arnold. Field guide to infrared systems, detectors, and FPAs / Arnold Daniels. − 2nd ed. p. cm. − (The field guide series) Rev. ed of: Field guide to infrared systems / Arnold Daniels. © 2007. Includes bibliographical references and index. ISBN 978-0-8194-8080-4 (alk. paper) 1. Infrared technology–Handbooks, manuals, etc. 2. Optical detectors—Handbooks, manuals, etc. 3. Focal planes–Handbooks, manuals, etc. I. Title. TA1570.D36 2010 621.362–dc22 2010000421 Published by SPIE P.O. Box 10 Bellingham, Washington 98227-0010 USA Phone: +1.360.676.3290 Fax: +1.360.647.1445 Email: books@spie.org Web: http://spie.org The content of this book reflects the work and thought of the author. Every effort has been made to publish reliable and accurate information herein, but the publisher is not responsible for the validity of the information or for any outcomes resulting from reliance thereon. Printed in the United States of America.
Introduction to the SeriesWelcome to the SPIE Field Guides—a series of publications written directly for the practicing engineer or scientist. Many textbooks and professional reference books cover optical principles and techniques in depth. The aim of the SPIE Field Guides is to distill this information, providing readers with a handy desk or briefcase reference that provides basic, essential information about optical principles, techniques, or phenomena, including definitions and descriptions, key equations, illustrations, application examples, design considerations, and additional resources. A significant effort will be made to provide a consistent notation and style between volumes in the series. Each SPIE Field Guide addresses a major field of optical science and technology. The concept of these Field Guides is a format-intensive presentation based on figures and equations supplemented by concise explanations. In most cases, this modular approach places a single topic on a page, and provides full coverage of that topic on that page. Highlights, insights, and rules of thumb are displayed in sidebars to the main text. The appendices at the end of each Field Guide provide additional information such as related material outside the main scope of the volume, key mathematical relationships, and alternative methods. While complete in their coverage, the concise presentation may not be appropriate for those new to the field. The SPIE Field Guides are intended to be living documents. The modular page-based presentation format allows them to be updated and expanded. We are interested in your suggestions for new Field Guide topics as well as what material should be added to an individual volume to make these Field Guides more useful to you. Please contact us at fieldguides@SPIE.org. John E. Greivenkamp, Series Editor College of Optical Sciences The University of Arizona The Field Guide SeriesField Guide to Geometrical Optics, John E. Greivenkamp (FG01) Field Guide to Atmospheric Optics, Larry C. Andrews (FG02) Field Guide to Adaptive Optics, Robert K. Tyson & Benjamin W. Frazier (FG03) Field Guide to Visual and Ophthalmic Optics, Jim Schwiegerling (FG04) Field Guide to Polarization, Edward Collett (FG05) Field Guide to Optical Lithography, Chris A. Mack (FG06) Field Guide to Optical Thin Films, Ronald R. Willey (FG07) Field Guide to Spectroscopy, David W. Ball (FG08) Field Guide to Infrared Systems, Arnold Daniels (FG09) Field Guide to Interferometric Optical Testing, Eric P. Goodwin & James C. Wyant (FG10) Field Guide to Illumination, Angelo V. Arecchi; Tahar Messadi; R.John Koshel (FG11) Field Guide to Lasers, Rüdiger Paschotta (FG12) Field Guide to Microscopy, Tomasz S. Tkaczyk (FG13) Field Guide to Laser Pulse Generation, Rüdiger Paschotta (FG14) Field Guide to Infrared Systems, Detectors, and FPAs, Second Edition, Arnold Daniels (FG15) Field Guide to Laser Fiber Technology, Rüdiger Paschotta (FG16) Field Guide to Infrared Systems, Detectors, and FPAs, 2nd EditionField Guide to Infrared Systems, Detectors, and FPAs, Second Edition, is written to clarify and summarize the theoretical and practical principles of modern infrared technology. It is intended as a reference for the practicing engineer and/or scientist who requires effective practical information to design, build, and/or test infrared equipment in a wide variety of applications. This book combines numerous engineering disciplines necessary for the development of an infrared system. It describes the basic elements involving image formation and image quality, radiometry and flux transfer, and explains the figures of merit for detector performance. It considers the development of search infrared systems and specifies the main descriptors used to characterize thermal imaging systems. Furthermore, this guide clarifies, identifies, and evaluates the engineering tradeoffs in the design of an infrared system. The 2nd edition provides the reader with an up-to-date view of the various third-generation infrared focal plane array (IRFPA) technologies currently in use or being actively researched. It also includes an overview of a new target acquisition model known as the “Targeting Task Performance (TTP) metric.” The applicability of this range performance model extends to sample imagers, digital image enhancement, and other features of modern imaging systems. I would like to acknowledge and express my gratitude to my professor and mentor Dr. Glenn Boreman for his guidance, experience, and friendship. The knowledge that he passed on to me during my graduate studies at CREOL ultimately contributed to the creation of this book. I also would like to thank Dr. Boreman for reviewing a draft copy of the IRFPA 2nd edition manuscript. I extend my sincere appreciation to Dr. Mel Friedman, NVESD, who took upon himself the onerous task of improving and clarifying the TTP metric concepts and its contents. Above all, I voice a special note of gratitude to my kids Becky and Alex and my wife Rosa for their love and support. Lastly, I would particularly like to thank you, the reader, for selecting this book and taking the time to explore the topics related to this motivating and exciting field. I trust that the contents of this book will prove interesting and useful to engineers and scientists working in one of the various infrared fields. This Field Guide is dedicated to the memory of my father and brothers. Arnold Daniels October 2010 Table of ContentsGlossary of Symbols xi Introduction 1 Electromagnetic Spectrum 1 Infrared Concepts 2 Optics 3 Imaging Concepts 3 Magnification Factors 4 Thick Lenses 5 Stops and Pupils 6 F-number and Numerical Aperture 7 Field of View 8 Combination of Lenses 9 Afocal Systems and Refractive Telescopes 10 Cold-Stop Efficiency and Field Stop 11 Image Quality 12 Image Anomalies in Infrared Systems 14 Infrared Materials 15 Ceramic and Amorphous Materials 19 GASIR Chalcogenide Glass Materials 20 Material Dispersion 21 Atmospheric Transmittance 23 Radiometry and Sources 24 Solid Angle 24 Radiometry 25 Radiometric Terms 26 Flux Transfer 28 Flux Transfer for Image-Forming Systems 29 Source Configurations 30 Blackbody Radiators 32 Planck’s Radiation Law 33 Stefan-Boltzmann and Wien’s Displacement Laws 35 Rayleigh-Jeans and Wien’s Radiation Laws 36 Exitance Contrast 37 Emissivity 38 Kirchhoff’s Law 39 Emissivity of Various Common Materials 40 Radiometric Measure of Temperature 41 Collimators 43 Performance Parameters for Optical Detectors 44 Infrared Detectors 44 Primary Sources of Detector Noise 45 Noise Power Spectral Density 46 White Noise 47 Noise-Equivalent Bandwidth (NEDΔf) 48 Shot Noise 50 Signal-to-Noise Ratio: Detector and BLIP Limits 51 Generation-Recombination Noise 52 Johnson Noise 53 1/f Noise and Temperature Noise 54 Detector Responsivity 55 Spectral Responsivity 57 Blackbody Responsivity 58 Noise-Equivalent Power 59 Specific or Normalized Detectivity 60 Photovoltaic Detectors or Photodiodes 61 Sources of Noise in PV Detectors 62 Expressions for D*PV,BLIP, D**PV,BLIP, and D* PV,JOLI 63 Photoconductive Detectors 64 Sources of Noise in PC Detectors 65 Third-Generation Infrared Imagers 66 Indium Antimonite (InSb) Photodiodes 67 Mercury Cadmium Telluride (HgCdTe) Photodetectors 68 Control of the Alloy Composition 69 HgCdTe Photodiodes and FPAs 70 DLHJ Photodiodes 71 Dual-Band HgCdTe FPAs 72 HDVIP Photodiodes 73 Uncooled HgCdTe Photodiodes 75 Quantum Well Infrared Photodetectors (QWIPs) 77 Types of QWIPs 80 Superlattices (SLs) 82 Multispectral QWIPs 83 Light Couplers 85 Pyroelectric Detectors 88 Pyroelectric Detectors—Mathematical Approach 90 Microbolometers 93 Microbolometers—Mathematical Approach 96 Infrared Dynamic Scene Simulators 99 Thermoelectric Detectors 100 Infrared Systems 101 Raster Scan Format: Single-Detector 101 Multiple-Detector Scan Formats: Serial Scene Dissection 103 Multiple-Detector Scan Formats: Parallel Scene Dissection 104 Staring Systems 105 Search Systems and Range Equation 106 Noise-Equivalent Irradiance 109 Performance Specification: Thermal-Imaging Systems 110 Modulation Transfer Function (MTF) Definitions 111 Optics MTF: Calculations 114 Electronics MTF: Calculations 116 MTF Measurement Setup and Sampling Effects 117 MTF Measurement Techniques: PSF and LSF 118 MTF Measurement Techniques: ESF and CTF 119 MTF Measurement Techniques: Noiselike Targets 121 MTF Measurement Techniques: Interferometry 123 Noise-Equivalent Temperature Difference (NETD) 124 NETD Measurement Technique 125 Minimum Resolvable Temperature Difference (MRTD) 126 MRTD: Calculation 127 MRTD Measurement Technique 128 MRTD Measurement: Automatic Test 129 Johnson Metric Methodology 130 Johnson Criteria Flaws 132 Targeting Task Performance (TTP) Metric Methodology 133 Human Vision—Distribution of Retinal Photoreceptors 134 Contrast Threshold Function (CTF) 136 Target Acquisition Performance 141 Probability of Task Performance 144 N50 to V50 Conversion (Example) 146 Acquisition Level Definitions 147 TTP Summary 148 Equation Summary 149 Bibliography 163 Index 167 GlossaryA Area Ad Detector area Aenp Area of an entrance pupil Aexp Area of an exit pupil Afootprint Footprint area Aimg Area of an image Alens Lens area Aobj Area of an object Aopt Area of an optical component As Source area AMTIR Amorphous materials transmitting infrared radiation ATR Automatic target recognition B 3-db bandwidth B-B Bound-to-bound B-C Bound-to-continuum B-QB Bound-to-quasi-bound b.f.l Back focal length BLIP Background-limited infrared photodetector c Speed of light in vacuum Cd Detector capacitance Cth Thermal capacitance CQWIP Corrugated quantum well infrared photodetector CTF Contrast transfer function CTFeye Contrast threshold function of the eye CTFn Contrast threshold function in the presence of external noise CTFsys Contrast threshold function of a system CVD Chemical vapor deposition ddiff Diameter of a diffraction-limited spot D Electrical displacement D* Normalized detectivity of a detector D*BF Background fluctuation D-star D*BLIP D-star under BLIP conditions D*TF Temperature fluctuation D-star D** Angle-normalized detectivity Denp Diameter of an entrance pupil Dexp Diameter of an exit pupil Dimg Image diameter Din Input diameter Dlens Lens diameter Dobj Object diameter Dopt Optics diameter Dout Output diameter DDCA Detector-Dewar cooler assembly DEE Digital emitter engine DLHJ Double-layer heterostructure junction DSS Dynamic scene simulator e Energy-based unit subscript Ebkg Background irradiance Eimg Image irradiance Esource Source irradiance EAPD Electron-injected avalanche photodiode ESF Edge spread function 𝛆 Energy of a photon 𝛆gap Energy gap of a semiconductor material f Focal length feff Effective focal length f0 Center frequency of an electrical filter f.f.l Front focal length f(x,y) Object function FB Back focal point FF Front focal point F(ξ,η) Object spectrum FOR Field of regard FOV Full-angle field of view FOVhalf-angle Half-angle field of view FPA Focal plane array F/# F-number g(x,y) Image function G Gain of a photoconductive detector G(ξ,η) Image spectrum GASIR Germanium arsenic selenium infrared material h Planck’s constant himg Image height hobj Object height h(x,y) Impulse response H Heat capacity H(ξ,η) Transfer function HDVIP High-density vertically integrated photodiode HIFOV Horizontal instantaneous field of view HFOV Horizontal field of view i Electrical current Mean current i1/f rms 1/f-noise current iavg Average electrical current ibkg Background rms current idark Dark current ij rms Johnson noise current iG/R Generation-recombination noise rms current inoise Noise current io Dark current ioc Open circuit current ipa Preamplifier noise rms current iph Photogenerated current irms rms current isc Short-circuit current ishot Shot noise rms current isig Signal current IC Integrated circuit IRFPA Infrared focal plane array J Current density k Boltzmann’s constant K Thermal conductance 𝓚(ξt) Spatial-frequency dependant MRTD proportionality factor lw Width of a well L Radiance Lbkg Background radiance Lv Visual luminance Lλ Spectral radiance LPE Liquid phase epitaxy LSF Line spread function LWIR Long-wave infrared M Exitance Mmeas Measured exitance Mobj Exitance of an object Mλ Spectral exitance MBE Molecular beam epitaxy MEMS Micro-electro-mechanical systems MQW Multiple quantum well MRTD Minimum resolvable temperature difference MTF Modulation transfer function MTFpre Pre-sampled MTF (optics detector, and line-of-sight jitter) MTFd Detector MTF MTFpost Post-sampled MTF (display, digital processing, and the eye-brain filter) MTFsys System’s MTF MWIR Midwave infrared m*e Effective mass of an electron ℳ Magnification ℳang Angular magnification n Refractive index ncycles Number of cycles to discriminate a target nd Number of detectors ne Number of photogenerated electrons nlines Number of lines NEI Noise-equivalent irradiance NEP Noise-equivalent power NEΔf Noise-equivalent bandwidth OTF Optical transfer function p Object distance p Pyroelectric coefficient p Momentum of an electron P Magnitude of internal polarization Pavg Average power Pchance Probability of chance Pmeasured Field-measured probability Pobserver Observer’s probability PC Photocurrent PSD Power spectral density PSF Point spread function PV Photovoltaic or photodiode q Image distance QW Quantum well QWIP Quantum well infrared photodetector R Resistance Rd Detector resistance Req Equivalent resistance Rin Input resistance RL Load resistance Rout Output resistance Rth Thermal Resistance RIIC Read-in integrated circuit ROIC Read-out integrated circuit 𝓡 Responsivity 𝓡i Current responsivity 𝓡v Voltage responsivity 𝓡(λ) Spectral responsivity 𝓡(T) Blackbody responsivity SCNtmp Scene contrast temperature SL Superlattices SNR Signal-to-noise ratio SR Strehl-intensity ratio SSRout Out-of-band spurious response ratio t Time T Temperature TB Brightness temperature Tbkg Background temperature TC Color temperature TCurie Curie temperature Td Detector temperature Tload Load temperature Trad Radiation temperature Tsource Source temperature Ttarget Target temperature TDMI Time-division-multiplexed integration TIR Total internal reflection TLHJ Triple-layer heterostructure junction TTP Targeting task performance metric TTPF Target transfer probability function υin Input voltage υj Johnson noise rms voltage υn rms noise voltage υoc Open-circuit voltage υout Output voltage υs Shot-noise rms voltage υsc Short-circuit voltage υscan Scan velocity υsig Signal voltage Mean voltage V Abbe number VIFOV Vertical instantaneous field of view VFOV Vertical field of view
proportionality factor x Alloy composition or molar fraction ratio α Thermal resistance coefficient α Coefficient of absorption β Blur angle caused by diffraction Δf Electronic frequency bandwidth Δt Time interval ΔT Temperature difference Δλ Wavelength interval ε Emissivity εo Permeability of a material η Quantum efficiency ηscan Scan efficiency η Spatial frequency in the vertical direction θ Angle variable θmax Maximum angle subtense Θ Seebeck coefficient λ Wavelength λcut Cutoff wavelength λmax Maximum wavelength λmax-cont Maximum contrast wavelength λpeak Peak wavelength λo Fixed wavelength Λ The de Broglie wavelength µ Vertical sample frequency ν Optical frequency ξ Spatial frequency in the horizontal direction ξcutoff Spatial cutoff frequency ξJ Johnson spatial frequency ρ Electric charge ρ Reflectance σ Standard deviation σ2 Variance σe Stefan-Boltzmann constant in energy units σeye rms visual noise expressed at a display σn rms noise filtered on by a display σp Stefan-Boltzmann constant in photon units τ Transmittance τatm Atmospheric transmittance τdwell Dwell time τext External transmittance τframe Frame time τint Internal transmittance τline Line time τopt Optical transmittance τRC Electrical time constant τth Thermal time constant υ Horizontal sample frequency ϕ Flux ϕabs Absorbed flux ϕbkg Background flux ϕd Detector flux ϕimg Flux incident on an image ϕinc Incident flux ϕobj Flux radiated by an object ϕsig Signal flux ϕtrans Transmitted flux ϕλ Spectral flux ψ Eigenfunction ω Angular frequency Ω Solid angle Ωd Detector solid angle Ωbkg Background solid angle Ωexp Exit pupil solid angle Ωenp Entrance pupil solid angle Ωimg Image solid angle Ωlens Lens solid angle Ωobj Object solid angle Ωs Source solid angle |
CITATIONS
Infrared radiation
Infrared imaging
Thermography
Sensors
Infrared sensors
Infrared detectors
Infrared telescopes
