Optical Sensors

Part I Basic principles and components 1 Introduction 1.1 History 1.1.1 17th Century 1.1.2 18th Century 1.1.3 19th Century 1.1.4 20th Century 1.2 Growth expectations 1.3 Book overview References 2 Light sources and detectors 2.1 Optical properties of light sources 2.1.1 Emission wavelength 2.1.2 Light coherence 2.1.3 Emission power 2.1.4 Light polarization 2.2 Incandescent sources 2.3 Light emitting diodes 2.4 Laser 2.4.1 Safety classes 2.5 Photodiodes, and phototransistors 2.5.1 Photodiodes 2.5.2 Phototransistors 2.6 Image sensors: CCD, and CMOS 2.6.1 Charge-coupled device (CCD) camera 2.6.2 Complementary metal-oxide–semiconductor (CMOS) camera 2.6.3 Comparison References 3 Maxwell equations 3.1 Introduction 3.2 Gauss’s law for electric fields 3.3 Gauss’s law for magnetic fields 3.4 Faraday’s law 3.5 Ampère–Maxwell law 3.6 Constitutive relations References 4 Electromagentic waves 4.1 Introduction 4.2 Electromagentic wave equation 4.2.1 Polarization 4.2.2 Poynting vector 4.3 Fresnel coefficients: reflection at an interface 4.3.1 S-polarization 4.3.2 P-polarization 4.3.3 Conservation of power 4.3.4 Brewster angle 4.4 Evanescent waves 4.5 Phase change 4-20 4.6 Reflection on a metallic interface References 5 Physical optics 5.1 Introduction 5.2 Optical interference 5.2.1 Double slit 5.2.2 Thin-film interference 5.3 Optical interferometers 5.3.1 Michelson interferometer 5.3.2 Mach–Zehnder interferometer 5.3.3 Fabry–Perot interferometer References 6 Diffraction 6.1 Introduction 6.2 Babinet’s principle 6.3 Huygens–Fresnel principle 6.4 Fraunhofer diffraction 6.4.1 Circular aperture 6.4.2 Multiple slits diffraction 6.4.3 Diffraction gratings 6.5 Fresnel diffraction References 7 Optical waveguides 7.1 Introduction 7.1.1 Design parameters 7.2 Slab waveguide 7.2.1 TE modes 7.2.2 Normalized parameters 7.2.3 TM modes 7.2.4 Optical confinement 7.3 Rectangular waveguides 7.3.1 Field shadows method 7.3.2 Normalized parameters 7.4 Optical fibers 7.4.1 Maxwell equations in cylindrical coordinates 7.4.2 Boundary conditions for optical fibers 7.4.3 Propagation modes 7.4.4 Normalized parameters References Part II Examples of optical sensors with lab exercises 8 Laser alignment 8.1 Justification 8.2 Equipment 8.3 Safety considerations 8.4 Procedure 8.4.1 Align the laser beam to a desired axis 8.4.2 Spatial filtering and collimation 9 Schlieren imaging 9.1 Justification 9.2 Equipment 9.3 Procedure References 10 Knife-edge technique 10.1 Justification 10.2 Theory 10.3 Equipment 10.4 Procedure 10.5 Optical chopper References 11 Triangulation method 11.1 Justification 11.2 Theory 11.3 Equipment 11.4 Procedure References 12 Refractive index and attenuation coefficient 12.1 Justification 12.2 Theory 12.3 Equipment 12.4 Procedure 12.5 Attenuation 12.5.1 Procedure References 13 Polarization and Brewster angle sensor 13.1 Justification 13.2 Theory 13.3 Equipment 13.4 Procedure References 14 Michelson interferometer lab 14.1 Justification 14.2 Theory 14.2.1 Measuring refractive index of glass 14.3 Equipment 14.4 Procedure 14.4.1 Wavelength measurement 14.4.2 Measuring the refractive index of glass References 15 Fabry–Perot interfereometer lab 15.1 Justification 15.2 Theory 15.2.1 Finesse 15.2.2 Free-spectral range 15.3 Equipment 15.4 Procedure 15.4.1 Measurement of source’s wavelength 15.4.2 Determination of sodium D-lines References 16 Fraunhofer and Fresnel diffraction lab 16.1 Justification 16.2 Theory 16.3 Equipment 16.4 Procedure 16.4.1 Fraunhofer diffraction single slit 16.4.2 Fraunhofer diffraction circular aperture 16.4.3 Fresnel diffraction straight edge 17 Spectrometer lab 17.1 Justification 17.2 Theory 17.3 Equipment 17.4 Procedure References Part III Applications of optical sensors 18 Light detection and ranging (LiDAR) 18.1 Introduction 18.2 Basic principles 18.3 Laser sources 18.3.1 Solid-state lasers 18.3.2 Fiber laser 18.3.3 Diode lasers 18.4 Scanner 18.4.1 Rotating mirrors 18.4.2 Micro-electro-mechanical systems mirrors 18.4.3 Solid-state lasers 18.4.4 Flash LiDAR 18.5 Other components 18.5.1 Control and data processing unit 18.5.2 Global navigation satellite system (GNSS) 18.5.3 Inertial measurement unit (IMU) 18.6 Applications 18.7 Challenges and future perspectives References 19 Optical biosensors 19.1 Introduction 19.2 Classification of optical sensors 19.2.1 Surface plasmon resonance (SPR) biosensors 19.2.2 Fluorescence-based biosensors 19.2.3 Guided-mode biosensors 19.3 Applications of optical biosensors 19.3.1 Environmental science 19.3.2 Food industry 19.3.3 Defense and homeland security 19.3.4 Health industry 19.4 Challenges and future perspectives 19.4.1 Limitations References Part IV Appendices Appendix A: Vector calculus Appendix B: Fields in waveguides and optical fibers Appendix C: Useful constants