Preface ..................................................... XI
1 Introduction ................................................. 1
References ................................................... 3
Part One The Optical Sensor Construction Kit
2 Light Sources ................................................ 7
2.1 Important Properties of Light Sources ................... 7
2.2 Thermal Light Sources ................................... 8
2.3 Line Sources ........................................... 12
2.4 Light Emitting Diodes (LEDs) ........................... 14
2.5 Lasers ................................................. 18
3 Photodetectors .............................................. 27
3.1 Photomultipliers ....................................... 27
3.2 Photodiodes ............................................ 30
3.3 Other Detector Types ................................... 31
3.4 Imaging Detectors ...................................... 33
3.5 Detector Noise ......................................... 35
4 Optical Elements ............................................ 37
4.1 Optical Materials ...................................... 37
4.2 Mirrors, Prisms and Lenses ............................. 39
4.3 Dispersive Elements: Prisms and Gratings ............... 42
4.4 Optical Filters ........................................ 43
4.5 Polarizers ............................................. 44
4.6 Optical Fibers ......................................... 46
4.7 Modulators ............................................. 49
References .................................................. 53
Part Two Optical Sensors and Their Applications ................ 55
5 Eyes: The Examples of Nature ................................ 57
5.1 The Compound Eyes of Insects ........................... 57
5.2 Nature's Example: The Human Eye ........................ 58
6 Optical Sensor Concepts ..................................... 63
6.1 Switches ............................................... 63
6.1.1 Light Barriers .................................. 63
6.1.2 Rain Sensor ..................................... 65
6.2 Spatial Dimensions ..................................... 66
6.2.1 Distance ........................................ 66
6.2.2 Displacement .................................... 71
6.2.3 Velocity ........................................ 75
6.2.4 Angular Velocity ................................ 83
6.3 Strain ................................................. 86
6.4 Temperature ............................................ 90
6.5 Species Determination and Concentration ................ 93
6.5.1 Spectrometry .................................... 94
6.5.2 Polarimetry ..................................... 98
6.5.3 Ellipsometry ................................... 102
6.5.4 Refractometry .................................. 104
6.5.5 Particle Density and Particle Number ........... 106
6.5.6 Fluorescence Detection ......................... 111
6.6 Surface Topography .................................... 114
6.6.1 Chromatic Confocal Sensors ..................... 115
6.6.2 Conoscopic Holography .......................... 117
6.6.3 Multiwavelength Interferometry (MWLI) .......... 118
6.6.4 White-Light Interferometry ..................... 119
6.6.5 Near-Field Optical Microscopy .................. 122
6.6.6 Contouring: Structured-Light Techniques ........ 123
6.6.7 Concepts: Cross-Correlation Analysis and 2D
Fourier-Transform Techniques ................... 125
6.7 Deformation and Vibration Analysis .................... 127
6.7.1 Laser Vibrometers .............................. 127
6.7.2 Speckle-Pattern Interferometry ................. 129
6.7.3 Holographic Interferometry ..................... 132
6.8 Wavefront Sensing and Adaptive Optics ................. 135
6.9 Determination of the Sun Angle ........................ 138
6.10 Determination of Age .................................. 140
References ................................................. 143
Part Three Optics and Sensors at Work: A Laser-Spectroscopic
Experiment .................................................... 147
7 The Measurement Problem .................................... 149
8 The Physical Principles behind the Experiment .............. 151
9 Spectroscopic Setups of the Experiment ..................... 155
9.1 The Single-Step Approach .............................. 155
9.2 The Two-Step Approach ................................. 158
References ................................................. 165
Summary .................................................... 167
Glossary ................................................... 169
Index ...................................................... 173
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