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Materials for infrared windows and domes : properties and performance /

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This text provides a comprehensive introduction to infrared-transparent materials for windows and domes that must withstand harsh environmental conditions, such as high-speed flight or high-temperature process monitoring. Each section contains introductory material that makes the book readable by an...

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Bibliographic Details
Main Author: Harris, Daniel C., 1948-
Corporate Author: Society of Photo-optical Instrumentation Engineers
Format: eBook
Language:English
Published: Bellingham, Wash. (1000 20th St. Bellingham WA 98225-6705 USA) : SPIE, [1999]
Series:SPIE monograph ; PM70.
Subjects:
Guided missiles > Optical equipment.
Infrared detectors.
Noses (Aircraft)
Electronic books.
Online Access:Connect to the full text of this electronic book
Table of Contents:
  • 1. Optical properties of infrared windows
  • 1.1. A day in the life of a photon
  • 1.2. Refraction and refractive index. 1.2.1. Birefringence; 1.2.2. Preference for cubic materials; 1.2.3. Reproducibility of the refractive index
  • 1.3. Reflection and transmission. 1.3.1. Transmission of an absorbing window; 1.3.2. Etalon effect
  • 1.4. Optical constants: n and k
  • 1.5. General behavior of absorption coefficient and refractive index
  • 1.6. Transmission spectra of infrared materials
  • 1.7. Measuring the absorption coefficient. 1.7.1. Direct transmittance measurements; 1.7.2. Laser calorimetry
  • 1.8. Emissivity
  • 1.9. Effect of temperature on absorption and emission
  • 1.10. Free carrier absorption in semiconductors
  • 1.11. What makes a window midwave or long wave?
  • 1.12. "Two-color" materials
  • References.
  • 2. Optical performance of infrared windows
  • 2.1. Resolution
  • 2.2. Scatter
  • 2.3. Modulation transfer function: a measure of imaging quality
  • 2.4. Degradation of infrared sensing by a hot window. 2.4.1. Emittance from a hot window; 2.4.2. Temperature gradients in windows
  • 2.5. Frequency doubling
  • 2.6. Microwave transmission properties of infrared materials
  • References.
  • 3. Mechanical properties
  • 3.1. Elastic constants
  • 3.2. Measuring the strength of brittle materials. 3.2.1. 3-point and 4-point flexure tests; 3.2.2. Equibiaxial disk flexure test
  • 3.3. Ceramics fracture at pre-existing flaws. 3.3.1. Stress concentration by cracks; 3.3.2. Strain rate dependence of strength
  • 3.4. Weibull statistics. 3.4.1. The Weibull distribution; 3.4.2. Safety factors
  • 3.5. Strength scales with area (or volume) under stress
  • 3.6. Strengths of optical ceramics. 3.6.1. Strength is not an intrinsic property of a material; 3.6.2. Temperature dependence of strength
  • 3.7. Window and dome design. 3.7.1. Designing a circular window; 3.7.2. Designing a dome
  • 3.8. Hardness and fracture toughness. 3.8.1. Relation of strength to fracture toughness and grain size; 3.8.2. Temperature dependence of hardness and fracture toughness
  • References.
  • 4. Thermal properties
  • 4.1. Thermal expansion and heat capacity
  • 4.2. Thermal conductivity
  • 4.3. Thermal shock. 4.3.1. Hasselman figures of merit; 4.3.2. Klein figure of merit for minimum thickness dome; 4.3.3. Mach-altitude limits for a dome
  • 4.4. Aerodynamic domes
  • 4.5. Thermal stability of window materials
  • References.
  • 5. Fabrication of infrared materials
  • 5.1. Classes of infrared materials. 5.1.1. Glass-ceramics
  • 5.2. Fabrication of polycrystalline materials by powder processing. 5.2.1. Yttria: an example of dome fabrication from a powder; 5.2.2. Methods of densifying ceramics: sintering, hot pressing and hot isostatic pressing; 5.2.3. Annealing
  • 5.3. Chemical vapor deposition. 5.3.1. Zinc sulfide and zinc selenide; 5.3.2. Silicon carbide and silicon nitride
  • 5.4. Single-crystal materials. 5.4.1. Gallium arsenide, gallium phosphide, germanium and silicon; 5.4.2. Sapphire; 5.4.3. Hot forging
  • 5.5. Optical finishing. 5.5.1. Scratch/dig specifications; 5.5.2. Optical polishing
  • 5.6. The effect of surface finish on mechanical strength
  • 5.7. Polymer infrared windows
  • References.
  • 6. Optical coatings
  • 6.1 Antireflection coatings. 6.1.1. Moth eye surfaces; 6.1.2. Interference fringes for measuring coating thickness; 6.1.3. Adherence of coatings; 6.1.4. Emittance from coatings; 6.1.5. Rugate filters
  • 6.2. Stress in coatings
  • 6.3. Conductive coatings for electromagnetic shielding
  • References.
  • 7. Erosion and Erosion Protection
  • 7.1. Rainfall characteristics
  • 7.2. The raindrop impact event
  • 7.3. Raindrop damage threshold velocity. 7.3.1. Threshold velocity for fracture or loss of mechanical strength; 7.3.2. Threshold velocity for loss of optical transmission or contrast; 7.3.3. Threshold velocity for loss of mass
  • 7.4. Rain erosion test facilities. 7.4.1. Whirling arm; 7.4.2. Single-impact waterjet; 7.4.3. Multiple-impact jet apparatus (MIJA); 7.4.4. Single-drop impact testing
  • 7.5. Aerodynamic effects in rain erosion
  • 7.6. Erosion by solid particles. 7.6.1. Combined effects of sand and rain
  • 7.7. Effect of angle of incidence on erosion. 7.7.1. Waterdrop impact at inclined angles; 7.7.2. Sand impact at inclined angles; 7.7.3. Comparative erosion testing of materials
  • 7.8. Protective coatings for erosion. 7.8.1. Mechanisms of protection by coatings; 7.8.2. Diamond-like carbon and germanium-carbon coatings; 7.8.3. "Boron phosphide" and other phosphorus-based coatings; 7.8.4. "REP" coating; 7.8.5. Claddings; 7.8.6. Diamond coatings
  • References.
  • 8. Proof testing
  • 8.1. Case study: proof testing of zinc selenide. 8.1.1. An example of an unsuccessful proof test
  • 8.2. What is the stress intensity factor?
  • 8.3. Slow crack growth
  • 8.4. The theory of proof testing. 8.4.1. How strength changes during a proof test; 8.4.2. A theoretical example: proof testing of sapphire
  • 8.5. Designing a proof test for the space shuttle window. 8.5.1. Minimum time to failure after a proof test; 8.5.2. Crack growth parameters for space shuttle window material; 8.5.3. Proof test design
  • 8.6. Fatigue
  • References.
  • 9. Optical-quality CVD diamond
  • 9.1. What is diamond and how is it made?. 9.1.1. Chemical vapor deposition of diamond; 9.1.2. The two surfaces of CVD diamond
  • 9.2. Mechanical and thermal properties of diamond. 9.2.1. Hardness, toughness and elastic properties; 9.2.2. Mechanical strength; 9.2.3. Thermal expansion; 9.2.4. Thermal conductivity and heat capacity; 9.2.5. Commercial grades of CVD diamond
  • 9.3. Optical properties of diamond. 9.3.1. Absorption and scatter; 9.3.2. Refractive index; 9.3.3. Microwave properties of diamond
  • 9.4. Diamond windows and domes. 9.4.1. Polishing diamond; 9.4.2. Mechanical and erosion performance; 9.4.3. Oxidation of diamond; 9.4.4. Prospects
  • References
  • Appendix A: Physical constants and conversion factors
  • Appendix B: Suppliers of infrared materials and sources of information
  • Appendix C: Optical properties of infrared materials
  • Appendix D: Definitions from radiometry
  • Appendix E: Elastic constants
  • Appendix F: The Weibull distribution
  • Appendix G: Thermal properties of selected materials
  • Index.
  • Preface
  • 0. The heat of the night and the dust of the battlefield
  • 0.1. Electromagnetic spectrum and atmospheric transmission
  • 0.2. Blackbody radiation
  • 0.3. Transmission through rain, snow, fog and dust
  • References.