Chapter 1. Introduction

History

1.2 Organization

Chapter 2. Radiometric Quantities, the Language

2.1 Angle and Solid Angle

2.2 Projected Area and Projected Solid Angle

2.3 Definitions of Basic Radiometric Quantities

2.4 Photonic Radiometric Quantities

2.5 Spectral Variables

2.6 Spectral Radiometric Quantities

2.7 Luminous Quantities

2.8 Fluometry

2.9 The Chinese Restaurant System

2.10 Recap

Chapter 3. Radiative Transfer

3.1 The Fundamental Equation of Radiative Transfer

3.2 Lambertian Emitters

3.3 Transfer between a Differential Element and a Disk

3.4 Other Geometries and Distributions

3.5 Recap

Chapter 4. Transmission, Reflection, Emission, and Absorption

4.1 Some Definitions

4.2 The Conservation of Power

4.3 Kirchhoff's Law

4.4 Absorption and Emission

4.5 Transmission and Reflection

4.6 Some Examples

4.7 Relationships among Transmissivity, Reflectivity, Absorptivity, and Emissivity

4.8 Recap

Chapter 5. Radiance

5.1 The Invariance of Radiance in a Vacuum

5.2 Invariance of (Reduced) Radiance across an Interface

5.3 The Invariance of Throughput

5.4 Path Radiance

5.5 Recap

Chapter 6. Sources

6.1 Laser Sources

6.1.1 Fixed-Wavelength Lasers

6.1.2 Tunable Lasers

6.2 Blackbodies

6.3 Cavity Radiators

6.4 Thermal Sources

6.4.1 Nernst Glower

6.4.2 The Globar

6.4.3 The Welsbach and Gas Mantles

6.4.4 Tungsten Bulbs

6.5 Recap

Chapter 7. Detectors

7.1 Detector Descriptions

7.2 Detector Types

7.3 Detector Noises

7.3.1 Johnson Noise

7.3.2 Shot Noise

7.3.3 Photon Noise

7.3.4 Temperature Noise

7.3.5 Generation-Recombination Noise

7.3.6 Excess Noise

7.4 Summary of Noises

7.5 Summary of Detector Properties

7.6 Some Real Problems

7.7 Recap

Chapter 8. Review of Optics

8.1 Photons, Waves, and Rays

8.2 Interference

8.2 Diffraction

8.3 The Thin Lens

8.4 Ray Traces

8.5 Paraxial Ray Traces

8.6 Aberrations

8.6.1 Spherical Aberration

8.6.2 Coma

8.6.3 Astigmatism

8.6.4 Curvature of Field

8.6.5 Distortion

8.6.6 Longitudinal Color

8.6.7 Lateral Color

8.7 Stops and Pupils

8.7.1 Aperture Stops and Pupils

8.7.2 Field Stops and Windows

8.8 Recap

Chapter 9. Normalization

9.1 The Need for Normalization

9.2 Effective Values

9.3 Photometry

9.4 An Illuminating Example

9.5 Other Normalizations

9.6 Normalization to the Peak

9.7 Normalization to the Average

9.8 Normalization to the Bandwidth

9.9 A Nasty Denormalization

9.9 Recap

Chapter 10. Calibration Standards

10.1 Types of Standards

10.2 Photometric Standards

10.3 Flux Standards

10.3.1 Source Standards

10.3.2 Electrical Substitution Radiometers

10.3.3 Self-Calibrating Detectors

10.4 Synchrotrons

10.5 Material Standards

10.5.1 Reflectance Standards

10.5.2 Transmittance Standards

10.6 Recap

Chapter 11. Measurement Techniques

11.1 Relative and Absolute Measurements

11.2 Errors

11.3 Rules of Measurement

11.4 The Measurement Equation

11.4.1 The Venus Radiometer Example

11.4.2 Spectral Variations

11.5 A Taxonomy of Measurements

11.6 Recap

Chapter 12. Measurement of Fluxes

12.1 Measurement of Power

12.2 Measurement of Incidence

12.3 Measurement of Exitance

12.4 Measurement of Intensity

12.5 Measurement of Radiance

12.6 Calibration Techniques for Radiometers

12.6.1 Distant, Point-Source Method

12.6.2 Distant, Extended-Source Method

12.6.3 Near, Extended-Source Method

12.6.4 Jones Technique

12.7 Recap

Chapter 13. Measurement of Material Properties

13.1 Total Hemispherical Emissivity

13.2 Spectral Directional Emissivity

13.3 Total Directional Emissivity

13.4 Specular Reflectivity

13.4.1 Substitutional Method

13.4.2 The Strong Method

13.4.3 The Bennett-Koehler Method

13.5 Specular Transmittance

13.6 Internal Transmittance and Absorption Coefficient

13.7 Directional-Hemispherical Reflection

13.7.1 The Coblentz Hemisphere

13.7.2 The Paraboloidal Reflectors

13.7.3 The Integrating Sphere

13.7.4 The Gier-Dunkle Cavity

13.8 Directional-Hemispherical Transmittance

13.9 Bidirectional Reflectance and Transmittance

13.10 Refractive Index

13.11 Recap

Chapter 14. Radiometric Temperatures

14.1 Radiometric Temperatures

14.1.1 Radiation Temperature

14.1.2 Radiance Temperature

14.1.3 Ratio Temperature

14.1.4 Color Temperature

14.1.5 Distribution Temperature

14.1.6 Ratio Temperature Difference

14.2 Atmospheric Transmission

14.3 Effective Temperature

14.4 Recap

Chapter 15. Polarization Effects

15.1 Descriptions of Polarization

15.2 Polarization from Dielectrics

15.3 Polarization from Metals

15.4 Polarization from Surface Scattering

15.5 Polarization from Slits

15.6 Polarization as a Result of Atmospheric Transmission

15.7 Representative Mueller Matrices

15.8 Recap

Appendix: Some Geometric Configuration Factors

Introduction

Preliminaries and Definitions

Plane Parallel Rectangles

Two Perpendicular Plane Rectangles

Contour Integration

Infinite Planes, Concentric Spheres and Infinitely Long Cylinders

Some Other Geometries

Summary and Overview

Introduction

Radiometry is an essential part of the optical design of almost every optical instrument. Such instruments are usually used to focus and detect radiation for some particular purpose, and for many applications it is absolutely essential to know how much radiation gets to the detector array or film in the image plane and the value of the resultant signal-to-noise ratio or exposure. Radiometry is almost essential in another sense, the measurement of the radiation of various objects. In fact, the word "radiometry" itself means the measurement of radiation. One cannot make the above-mentioned calculations without a knowledge of the flux from the source, whether it be a tungsten bulb or a sun-illuminated vista. Therefore, this text on radiometry involves both the techniques of calculating radiative transfer and the measurement of fluxes and radiometric properties of different sorts.

1.1 History

The most primitive beginnings of radiometry must have been the observation by early man of the different brightnesses of stars and the sensing of the warmth from the sun and the fire (after he invented or discovered it). These were radiometric measurements, but they surely were not quantitative. Greek astronomers, especially Ptolemy and Hipparchus, made good estimates of star magnitudes, and these were extended by Galileo.

The history of quantitative radiometry surely begins with the practice of photometry, the measurement of visible light. It was first put on an organized basis by Pierre Bouguer in 1729 when he described an instrument that could compare the brightnesses of two sources. In 1760 Johann Lambert enunciated the law of the addition of illumination, the inverse square law, cosine law of flux density distribution, and others. Many relatively small advances were made until Becquerel observed the photoelectric effect in 1839. Then the photoconductive effect was discovered by Willoughby Smith in 1873 and the photoemissive effect by Hertz in 1887. These discoveries moved the different measurement instruments out of the realm of human observation and into that of quantitative analyses. Although the eye is a wonderful comparison device, it is notoriously poor at measuring radiation levels. Additional history is available in the very nice photometry text by Walsh and the one on absolute radiometry by Hengstberger.

1.2 Organization

The scheme of this text is to discuss first some of the basic concepts, the language of radiometry, and relatively simple radiative transfer. The methods used to describe the properties of radiators, reflectors, and transmitters are next described. Then ideal and practical sources are covered. Normalization, an interesting part of the field, involving making measurements and calculations of radiative quantities based on responses of certain sensors, is covered next. Radiometric standards are then described, just before measurement and calibration techniques. Radiometric, sometimes known as fake, temperatures are described along with their errors. Concepts of polarization are then discussed, mostly in terms of warnings.