Optical Sensors and Microsystems (eBook)

PREFACE 5
CONTENTS 7
TECHNOLOGY 10
ADVANCED OPTOELECTRONICS IN OPTICAL FIBRE SENSORS 11
1. INTRODUCTION 11
2. LASERS AND AMPLIFIERS 12
3. NON LINEAR OPTICS IN SENSOR SYSTEMS 14
4. STRANGE AND DIFFERENT PROPAGATION PHENOMENA 17
5. INTEGRATED OPTICS AND MICROMACHINING 20
6. OPTICAL SIGNAL DETECTION SYSTEMS 21
7. CONCLUSIONS 21
INTERFEROMETRIC DISTANCE SENSORS 23
1. INTRODUCTION 23
2. INTERFEROMETRIC DISTANCE MEASUREMENTS 23
2.1 Displacement measurements 24
3. DOUBLE WAVELENGTH INTERFEROMETRY 26
4. FREQUENCY-MODULATED INTERFEROMETRY 30
5. WHITE LIGHT INTERFEROMETRY 32
5.1 Optical sources for white light interferometry. 32
5.2 Mechanically scanned white light interferometer 33
5.3 Electronic-scanning white light interferometry 35
5.4 Dispersive white light interferometry 35
6. COMPARISON OF THE DIFFERENT TECHNIQUES 37
REFERENCES 38
OPTICAL TOMOGRAPHY: TECHNIQUES AND APPLICATIONS 40
1. INTRODUCTION 40
2. OPTICAL TOMOGRAPHY 42
3. TIME-RESOLVED IMAGING 42
4. FLUORESCENCE IMAGING 42
5. COHERENCE IMAGING 43
6. DIRECT TRANSILLUMINATION IMAGING 44
7. OPTICAL TOMOGRAPHY SCANNERS 44
8. CONCLUSIONS 45
REFERENCES 45
OPTICAL WAVEGUIDE REFRACTOMETERS 47
1. INTRODUCTION 47
2. REFRACTOMETERS FOR LIQUIDS: AN OVERVIEW 48
2.1. Classical refractometers 48
2.2. Interferometric refractometers 49
2.3. Non conventional refractometers 49
2.4. Optical fiber refractometers 50
2.5. Waveguide refractometers 51
3. CERENKOV REFRACTOMETRY 52
4. INVERSE USE OF CERENKOV REFRACTOMETRY 55
5. CONCLUSIONS 56
REFERENCES 57
CHARACTERIZATION OF AN OPTICAL FIBRE pH SENSOR WITH METHYL RED AS OPTICAL INDICATOR 58
1. INTRODUCTION 58
2. OPTICAL FIBRE PROBE 58
3. SPECTROPHOTOMETRIC ANALYSIS: PHOTODEGRADATION 59
4. OPTICAL FIBRE SENSOR 60
5. IONIC STRENGTH EFFECTS 62
CONCLUSIONS 64
REFERENCES 65
OPTICAL SENSORS AND MICROSYSTEMS USING LIQUID CRYSTALS 66
1. INTRODUCTION 66
2. LIQUID CRYSTALS OPTICAL AND ELECTRO-OPTICAL PROPERTIES 67
3. OPTICAL SENSORS UTILISING LIQUID CRYSTALS 73
4. OPTICAL MICROSYSTEMS UTILISING LIQUID CRYSTALS 76
5. OUR EXPERIMENTAL WORK 78
6. CONCLUSIONS 80
REFERENCES 81
INDIUM TIN OXIDE FILMS FOR OPTICAL SENSORS 83
1. INTRODUCTION 83
2. CHARACTERISTICS OF INDIUM TIN OXIDE 83
3. DEPOSITION PROCESS 84
4. PHOTOCONDUCTIVE EFFECT 84
5. PHYSICAL INTERPRETATION OF THE OBSERVED PHENOMENA 86
6. REVERSIBILITY OF THE VARIATIONS OF THE RESISTIVITY AND FACTORS THAT INFLUENCE THE SPEED OF RETURN TO THE INITIAL CONDITIONS 86
7. POSSIBLE APPLICATIONS OF THE PHOTOCONDUCTIVE EFFECT 88
8. CONCLUSIONS 89
REFERENCES 89
OPTOELECTRONIC NEURAL NETWORKS 90
1. INTRODUCTION 90
2. OPTOELECTRONIC NEURAL PROCESSING 90
3. OPTOELECTRONIC NEURAL NETWORKS 92
4. SPATIAL LIGHT MODULATORS AND VERTICAL CAVITY SURFACE EMITTING LASERS IN NEURAL SYSTEMS 94
5. OPTOELECTRONIC NEURAL SYSTEM FOR OPTICAL SENSOR SIGNAL PROCESSING 95
6. RESULTS OF EXPERIMENTS 97
7. CONCLUSIONS 99
REFERENCES 99
COMPLEX ABCB-MATRICES: A GENERAL TOOL FOR ANALYZING ARBITRARY OPTICAL SYSTEMS 100
1. INTRODUCTION 100
2. COMPLEX ABCD-MATRICES 101
3. SPACE-TIME LAGGED COVARIANCE FOR COMPLEX ABCD SYSTEMS 104
4. LASER DOPPLER AND LASER TIMEOF-FLIGHT VELOCIMETERS 108
5. OUT-OF-PLANE ANGULAR DISPLACEMENT 110
6. IN-PLANE ANGULAR DISPLACEMENTS 113
7. TORSION ANGLE SENSOR 114
8. ROTATIONAL SPEED AND TORSIONAL VIBRATIONS OF A ROTATING SHAFT 114
9. CONCLUSION 116
REFERENCES 117
MICROSYSTEMS AND RELATED TECHNOLOGIES 118
1. INTRODUCTION 118
2. OVERVIEW OF TECHNOLOGIES SUITABLE FOR MICROSYSTEMS. 119
2.1 Bulk Micromachining 119
2.2 Surface Micromachining 121
2.3 Mold Micromachining 123
2.4 Porous silicon 124
2.5 Gallium arsenide: an interesting material for micromechanics 125
2.6 Thin film technology 126
3. AN EXAMPLE OF MICROSTRUCTURES : A MICROHEATER ARRAY FOR SELECTIVE GAS SENSING 126
3.1 Design and simulation 126
3.2 Device fabrication and performance 129
4. CONCLUSIONS 130
REFERENCES 130
THE STRETCH-AND-WRITE TECHNIQUE FOR FABRICATION OF FIBER BRAGG- GRATING ARRAYS 132
1. INTRODUCTION 132
2. FBG-ARRAY FABRICATION AND CHARACTERIZATION 133
3. FBG SENSING APPLICATIONS 135
4. FBG-ARRAYS FOR TELECOMMUNICATION SYSTEMS 135
5. CONCLUSIONS 137
REFERENCES 138
APPLICATIONS 139
FLUORESCENCE LIFETIME-BASED SENSING FOR BIOPROCESS AND BIOMEDICAL APPLICATIONS 140
1. INTRODUCTION 140
2. pCO2 RESONANCE ENERGY TRANSFER SENSOR 141
3. pCO2 SENSOR FABRICATION 142
REFERENCES 143
A PIEZOELECTRIC BIOSENSOR AS A DIRECT AFFINITY SENSOR 144
1. INTRODUCTION 144
2. SENSOR PRINCIPLE 144
2.1. Measurement of the Resonant Frequency 145
2.2. Measurement Procedure 145
2.3. Chemicals 146
3. ADSORPTION EXPERIMENTS 146
4. AFFINITY SENSING EXPERIMENT 147
4.1. Covalent immobilization of the 2,4-D: 148
4.2. Modification of the 2,4-D for coupling 148
5. CONCLUSIONS 150
REFERENCES 150
THE COMPLEX PHASE TRACING BASED SHAPE EVALUATION SYSTEM FOR ORTHOPAEDIC APPLICATION 152
1. INTRODUCTION 152
2. PRINCIPLE OF THE MEASUREMENT 153
3. COMPLEX PATTERN RECONSTRUCTION AND CORRECTION OF THE PHASE ERROR 155
REFERENCES 158
OPTICAL FIBRE CHEMICAL SENSORS FOR ENVIRONMENTAL AND MEDICAL APPLICATIONS 159
1. INTRODUCTION 159
2. SENSING PRINCIPLES 160
2.1 Absorption 160
2.2 Fluorescence 161
2.3 Plasmon Resonance 163
2.4 Raman Scattering 163
2.5 Chemiluminescence 164
3. THE PROBE AND THE OPTICAL LINK 164
3.1 Sensing Mechanisms 164
3.2 The Probe 165
3.3 The Optical Link 166
4. OPTICAL FIBRE SENSORS FOR ENVIRONMENTAL APPLICATIONS 167
4.1 Pesticides 167
4.2 Hydrocarbons and Related Derivatives 170
4.3 Biological Oxygen Demand 172
5. OPTICAL FIBRE SENSORS FOR BIOMEDICAL APPLICATIONS 173
5.1 Bile 173
5.2 pH 174
5.3 Oxygen 178
5.4 Carbon Dioxide 179
6. CONCLUSIONS 180
REFERENCES 180
INTRODUCTION TO THE MULTICOMPONENT ANALYSIS WITH ARRAYS OF NON- SELECTIVE CHEMICAL SENSORS 183
1. INTRODUCTION 183
2. QUANTITATIVE ANALYSIS 185
2.1 Chemometrics 186
2.1.1 Multiple Linear Regression: 188
2.1.2 Principal Component Regression: 188
3. QUALITATIVE ANALYSIS (ELECTRONIC NOSE) 188
4. SELF ORGANIZING MAP (SOM) 190
4.1 Tools for Sensor Array Modeling and Data Analysis 191
4.1.1 Data classification: 191
4.1.2 Evaluation of single sensors contribution: 191
4.1.3 Sensor drift effects: 191
REFERENCES 192
HIGH SENSITIVITY TRACE GAS MONITORING USING SEMICONDUCTOR DIODE LASERS 193
1. INTRODUCTION 193
1.1 Detector noise 194
1.2 Laser Excess Noise 195
1.3 Residual Amplitude Modulation 196
1.4 Interference Fringes 196
1.5 Detection Techniques 197
1.6 Bandwidth reduction 198
2. EXPERIMENTAL SET-UP 199
3. RESULTSANDDISCUSSION 201
3.1 Ammonia NH3 201
3.2 Carbon Monoxide CO, Carbon DioxideCO2 and Hydrogen SulphideH2S 201
3.3 Molecular Oxygen O2 201
3.4 Hydrogen Chloride HCl 202
4. CONCLUSION 202
REFERENCES 203
OPTICAL FIBER SENSORS FOR THE NUCLEAR ENVIRONMENT 204
1. INTRODUCTION 204
2. POTENTIAL NEEDS FOR OFS(N) IN NUCLEAR POWER PLANTS 204
2.1 The Nuclear Fuel Cycle : From Mining to Waste Conditioning 204
2.2 Nuclear Power Plant instrumentation improvement 204
3. ANALYSIS & EXPERIMENTS OF SOME OFS &
3.1 Nuclear shield monitoring 206
3.1.1 Bragg gratings for structure monitoring. 206
3.1.2 Sensitivity of Bragg gratings to main physical parameters. 207
3.1.3 Bragg grating behaviour under .-ray irradiation. 207
3.1.4 Bragg grating extensometer' experiments with concrete. 208
3.2 Hydrogen risk 214
3.2.1 Motivations for safety. 214
3.2.2 "H2 risk" monitoring system specifications. 214
3.2.3 System development and experiments. 214
3.2.4 Experimental. 215
3.2.5 Conclusion. 216
3.3 Steam pipe monitoring 218
3.3.1 OTDR Method. 219
3.3.2 In-Fiber Bragg Grating technology. 219
3.4 Nuclear radiation detection 220
3.5 Waste conditioning and disposal monitoring 221
4. CONCLUSION 223
REFERENCES 223
CRLORINATED HYDROCARBONS TRACE DETECTION IN WATER BY SPARGING AND LASER IR GAS PHASE DETECTION 226
1. INTRODUCTION 226
2. GENERAL ABOUT THE SPARGING TECHNIQUE 226
3. PROJECT DEVELOPMENTS AT TRI LAB 227
4. CONCLUSIONS 231
LEGENDA OF SYMBOLS 232
REFERENCES 232
HOLLOW CORE FIBER GUIDES AS GAS ANALYSIS CELLS FOR LASER SPECTROSCOPY 234
1. INTRODUCTION 234
2. TDLAS EXPERIMENTS WITH HOLLOW WAVEGUIDES GAS CELLS ( IRGAS PROJECT, TRI LAB) 235
3. CONCLUSIONS 238
REFERENCES 238
CHEMILUMINESCENCE IMAGING OF PLANT ORIGIN MATERIALS 240
1. INTRODUCTION 240
2. MATERIALS AND METHODS 241
2.1 Instrumentation 241
2.1.1 Single photon counting imaging. 241
2.1.2 Spectral analysis. 242
2.2 Methods 244
3. RESULTS AND DISCUSSION 245
3.1 CL of cereal food products 245
3.2 Photoinduced Chemiluminescence of wood 247
4. CONCLUSIONS 250
REFERENCES 250
OPTICAL FIBER SENSORS FOR THE CULTURAL HERITAGE 251
1. INTRODUCTION 251
2. OPTICAL FIBERS FOR MONITORING THE EFFECTS OF TEMPERATURE ON PICTURE VARNISHES 251
3. THE MONITORING OF LIGHTING IN MUSEUM ENVIRONMENTS BY MEANS OF OPTICAL FIBERS 254
4. CONCLUSIONS 255
REFERENCES 256
FIBER OPTICS REFLECTANCE SPECTROSCOPY: A NON- DESTRUCTIVE TECHNIQUE FOR THE ANALYSIS OF WORKS OF ART 257
1. INTRODUCTION 257
2. EXPERIMENTAL 258
3. PIGMENT IDENTIFICATION 259
4. CONCLUSION 261
REFERENCES 263
OPTICAL DIAGNOSTIC SYSTEMS AND SENSORS TO CONTROL LASER CLEANING OF ARTWORKS 264
1. INTRODUCTION 264
2. THE CLEANING PROCESS 264
3. IMAGE DIAGNOSTICS 266
3.1. Analysis 267
3.1.1. QS pulses. 267
3.1.2. SFR pulses. 269
4. OPTICAL SENSOR 271
REFERENCES 271
ELECTRO-OPTICAL SENSORS FOR MECHANICAL APPLICATIONS 272
1. INTRODUCTION 272
2. E-O SENSORS IN MECHANICAL INDUSTRY: RATIONALE 273
3. EXAMPLES OF APPLICATIONS OF ELECTROOPTIC SENSORS TO MECHANICAL MEASUREMENTS 274
3.1 Dimensional control 274
3.2 Tests of surface properties of industrial manufacts 276
3.3. 3-D Macro- and Microprofilometry 276
3.4. Color measurements 278
4. PERSPECTIVES 278
REFERENCES 286
OPTICAL FIBRES AND THEIR ROLE IN SMART STRUCTURES 287
1. INTRODUCTION 287
2. THE MEASUREMENT REQUIREMENTS - SENSING ON A LARGE SCALE 290
3. THE MEASUREMENT PROCESS - POINT DISTRIBUTED AND QUASI DISTRIBUTED SENSING 291
4. WHY USE FIBRE OPTICS 292
5. PHYSICAL MEASUREMENTS - STRAIN AND TEMPERATURE FIELDS 292
6. CHEMICAL MEASUREMENTS IN STRUCTURAL MONITORING – SAFETY AND CORROSION 296
7. CONCLUSIONS 299
REFERENCES 300
ALL OPTICAL FIBER ULTRASONIC SOURCES FOR NON DESTRUCTIVE TESTING AND CLINICAL DIAGNOSIS 302
1. INTRODUCTION 302
2. THEORETICALBACKGROUND 303
3. FIBER OPTIC ULTRASONIC SOURCE DESIGN 305
4. EXPERIMENTAL SETUP AND RESULTS 306
5. CONCLUSION 310
REFERENCES 310
INDEX 311

COMPLEX ABCB-MATRICES: A GENERAL TOOL FOR ANALYZING ARBITRARY OPTICAL SYSTEMS (p. 97-98)


1. INTRODUCTION

In this paper, we describe a novel formulation of light beam propagation through any complex optical system that can be described by an ABCD ray-transfer matrix.1,2 Within the framework of complex ABCD-optical systems, we then present novel speckle methods for analyzing linear and angular velocities and displacements. All methods rely on the dynamics of speckle patterns, produced by scattering of coherent light off solid surfaces undergoing angular and/or translational displacements.

Coherent light scattered off a rough surface produces a granular diffraction pattern some distance away from the object. This pattern is referred to as speckles,3 and originates from elementary interference of the waves emanating from many microscopic areas on the surface within the illuminated region. If the illuminated object is in motion, the resulting speckle pattern also evolves with time, i.e., a dynamical speckle pattern results. The target motion or displacement is usually determined by calculating the space- or time-lagged covariance of the detector currents before and after object displacement: and then determine the position where the peak of the covariance attains its maximum.

We first present the basic properties of the ABCD ray-matrix method,1,2 and summarize raymatrices for Simple optical elements,5 e.g., thin lenses, mirrors, and free-space propagation. Additionally, we present the ray-transfer matrix for a Gaussian shaped aperture.1,2 Thus, armed with matrix elements describing the most common elements in an optical system, the resulting ray-transfer matrix can be obtained for most systems encountered in practice. The resulting raytransfer matrix connects the input ray position and slope with the corresponding output parameters. Rather than dealing with rays, a Gaussian Green’s function has been developed,1,2 valid for arbitrary ABCD systems, to reveal the transition of the field in the input plane, through the ABCD-optical system, to the output plane.

Armed with the Green’s function that reveals the field in the output plane of an arbitrary ABCD-system, provided the field in the input plane is known, we then present a general equation, valid for arbitrary ABCD-optical systems, for the space-time lagged covariance of photocurrent: The position where the Gaussian-shaped covariance attains its maximum reveals information about target velocity or displacement. We discuss, how, in practice, the target velocity/ displacement is assessed. The theoretical results alluded to above are then applied to a series of novel optical sensor applications, all described by the ABCD kernel.

Two systems for measuring hear velocities, viz. the laser Doppler velocimeter6 and the laser time-of-flight velocimeter,7,8 are presented. A compact system for measuring linear surface velocities is presented, where all passive optical components are replaced with a single holographic optical element.9 Additionally, other novel schemes for further system miniaturization are presented.

We then present a new method for measurement of out-of-plane angular displacement in one or two dimensions.12,13 It is demonstrated that the angular displacement sensor is insensitive to both object shape and target distance, and any transverse or longitudinal movements of the target. It is further shown that the method has a resolution of 0.3 mdeg (5 µrad). A new method for measuring in-plane angular velocities or displacements are then presented.14 Here, we consider off-axis illumination, and it is shown that, for Fourier transform optical systems, in-plane rotation causes the speckles to translate in a direction perpendicular to the direction of surface motion, whereas for an imaging system, the translation is parallel to the direction of surface motion. Based on this, we discuss a novel method, which is independent of both the optical wavelength and the position of the laser spot on the object, for determining either the angular velocity or the corresponding in-plane displacement of the target object. The out-of-plane angular displacement sensor can be modified to measure the distribution of static torsion angles of targets undergoing twisting motion.15 Because the torsion angle sensor is independent of object shape, we measure the distribution of torsion angles in both uniform and non-uniform deformation zones.

Finally, we present a novel method for measuring out-of-plane angular velocities. Besides measuring angular velocities, the sensor can measure, simultaneously, torsional vibrations of the rotating shaft.