Table of Contents

Preface

1 Geometrical Optics

1.1 General Comments

1.2 Snell's Law

1.3 Total Internal Reflection

1.4 Paraxial Approximation

1.5 Lenses

     1.5.1 Lens types

     1.5.2 Positive lenses

     1.5.3 Negative lenses

     1.5.4 Cardinal points

     1.5.5 Nodal points

1.6 Rays and Planes

     1.6.1 Tangential planes and tangential rays

     1.6.2 Sagittal planes, sagittal rays, and skew rays

1.7 Stops and Pupils

     1.7.1 Definitions

     1.7.2 Example 1: a schematic microscope

     1.7.3 Example 2: a schematic microscope with two additional apertures

     1.7.4 Example 3: a real double Gauss lens

     1.7.5 Single-lens model of a complex lens

1.8 Analytical Modeling of a Lens and Rays

     1.8.1 Some comments

     1.8.2 Rules of sign for lens focal length and surface radius of curvature

     1.8.3 Derivation of the paraxial focal length for a lens

     1.8.4 Derivation of the thin lens equation for a thin lens

     1.8.5 Derivation of the focal length of two thin lenses

     1.8.6 Application examples of the thin lens equation for a positive lens

     1.8.7 Application examples of the thin lens equation for a negative lens

1.9 Lateral and Axial Magnifications of Lenses

     1.9.1 Definition of lateral magnifications and axial magnifications

     1.9.2 Schematic examples of an image formed by a positive lens

     1.9.3 Schematic examples of an image formed by a negative lens

     1.9.4 Distortion of a 3D image formed by a perfect lens

1.10 Mirrors

     1.10.1 Reflection law

     1.10.2 Mirror equation: lateral and axial magnifications

1.11 Mirror Imaging

     1.11.1 Planar mirror imaging

     1.11.2 Convex mirror imaging

     1.11.3 Concave mirror imaging

1.12 Optical Aberrations

     1.12.1 Spherical aberration

     1.12.2 Coma

     1.12.3 Astigmatism

     1.12.4 Color aberrations

     1.12.5 Field curvatures

     1.12.6 Wavefront errors and optical path difference

     1.12.7 How to read an OPD diagram

1.13 Evaluation of Image Quality

     1.13.1 Image resolution: Rayleigh criterion

     1.13.2 US Air Force resolution test chart

     1.13.3 Image resolution: contrast transfer function

     1.13.4 How to read a CTF diagram

     1.13.5 Image resolution: modulation transfer function

     1.13.6 Effect of sensor pixel size: Nyquist sampling theorem

     1.13.7 Image distortion

1.14 Illumination Optics versus Imaging Optics

1.15 Radiometry

     1.15.1 Lambert's cosine law

     1.15.2 Light-collecting power of a lens

     1.15.3 Inverse square law

     1.15.4 A point illuminated by a circular Lambertian source

     1.15.5 A working plane illuminated by a point source: the cos⁴(μ) off-axis relation

     1.15.6 Etendue and radiance conservation

     1.15.7 Radiometry and photometry

     1.15.8 Blackbody

References

2 Wave Optics

2.1 Wave Equation

2.2 Polarization

     2.2.1 Definition

     2.2.2 Linear and random polarization

     2.2.3 Elliptical and circular polarizations

2.3 Reflectance and Transmittance of an Optical Interface

     2.3.1 Reflectance and transmittance

     2.3.2 Brewster's angle and total reflection

     2.3.3 Phase change in reflections

2.4 Interference

     2.4.1 Two-wave interference

     2.4.2 Multiwave interference

2.5 Diffraction

     2.5.1 Single-slit diffraction

     2.5.2 Circular diffraction

     2.5.3 Comparison with a Gaussian pattern

References

3 Gaussian Beam Optics

3.1 Gaussian Beam Equations

3.2 Beam Size Characteristics

3.3 Beam Wavefront Characteristics

3.4 Intensity and Power

3.5 Graphic Explanations of Laser-Beam-Propagation Characteristics

3.6 Thin Lens Equation for a Real Laser Beam

3.7 Collimating and Focusing: Maximum and Minimum Focusing Distance

3.8 Two Examples of Focusing or Collimating Laser Beams

     3.8.1 Focusing a He-Ne laser beam

     3.8.2 Collimating a laser diode beam

     3.8.3 Focusing a Gaussian beam versus focusing a planar wave

References

4 Optical Materials

4.1 Properties 89

     4.1.1 Refractive index

     4.1.2 Abbe number

     4.1.3 Transmission spectral range

     4.1.4 Deviation of partial dispersion

     4.1.5 Refractive-index temperature dependence

     4.1.6 Thermal expansion

     4.1.7 Chemical stabilities

     4.1.8 Density

     4.1.9 Mechanical and electrical properties

     4.1.10 Melting temperature

     4.1.11 Price

     4.1.12 Availability

4.2 Optical Glasses

     4.2.1 Glass types

     4.2.2 Glass brands

4.3 Optical Polymers

4.4 UV Optical Materials

4.5 IR Optical Materials

4.6 Mirror Substrates

4.7 Crystals

     4.7.1 Crystals for making optical components

     4.7.2 Crystals for opto-electrical devices and nonlinear applications

References

5 Optical Coatings

5.1 Metallic Coatings

5.2 Dielectric Coatings

5.3 Antireflection Coatings

5.4 High-Reflection Coatings

5.5 Beamsplitting Coatings

5.6 Polarizing Coatings

5.7 Spectral Coatings

5.8 Electrical Conductive Coatings

References

6 Optical Components

6.1 Lenses

     6.1.1 Lens specifications

     6.1.2 Spherical lenses

     6.1.3 Singlets, doublets, and triplets

     6.1.4 Aspheric surfaces

     6.1.5 Aspheric lenses

     6.1.6 Cylindrical lenses

     6.1.7 Gradient-index lenses

     6.1.8 Fresnel lenses

     6.1.9 Diffractive lenses

     6.1.10 Lens materials

6.2 Mirrors

     6.2.1 Mirror types and specifications

     6.2.2 Metallic mirrors and dielectric (dichroic) mirrors

     6.2.3 Spectral mirrors

     6.2.4 Spherical mirrors

     6.2.5 Elliptical mirrors

     6.2.6 Parabolic mirrors

     6.2.7 Hyperbolic mirrors

6.3 Prisms

     6.3.1 General comments

     6.3.2 Dispersion prisms

     6.3.3 Right-angle prisms

     6.3.4 Corner reflectors

     6.3.5 Penta prisms

     6.3.6 Dove prisms

     6.3.7 Pechan prisms

     6.3.8 Anamorphic prisms

6.4 Non-Polarizing Beamsplitters

     6.4.1 General comments

     6.4.2 Cubic non-polarizing beamsplitters

     6.4.3 Plate non-polarizing beamsplitters

     6.4.4 Pellicle non-polarizing beamsplitters

     6.4.5 Polka-dot non-polarizing beamsplitters

6.5 Polarizing Beamsplitters

     6.5.1 General comments

     6.5.2 Typical performances

6.6 Polarizers

     6.6.1 Birefringent polarizers

     6.6.2 Wire-grid polarizers

     6.6.3 Thin film polarizers

6.7 Spectral Filters

     6.7.1 Dielectric coating filters

     6.7.2 Colored-glass filters

6.8 Wave Plates

     6.8.1 Working principle

     6.8.2 Crystal-quartz wave plates

     6.8.3 Achromatic and tunable wave plates

6.9 Attenuators

6.10 Diffusers

6.11 Diffraction Gratings

     6.11.1 General description

     6.11.2 Grating equation

     6.11.3 Dispersion power

     6.11.4 Blazing angle

     6.11.5 Grating efficiency

     6.11.6 Grating types 153

6.12 Optical Fibers

     6.12.1 General description

     6.12.2 Numerical aperture

     6.12.3 Mode structures in a cylindrical waveguide

     6.12.4 V-number

     6.12.5 Single-mode fibers

     6.12.6 Multimode fibers

     6.12.7 Modal dispersion

     6.12.8 Mode field diameter

     6.12.9 Attenuation

     6.12.10 Polarization

     6.12.11 Fiber bundles for image delivery

     6.12.12 Fiber-bundle and liquid light guides

     6.12.13 Fiber adaptors, couplers, and lab supplies

6.13 Photodetectors

     6.13.1 General comments

     6.13.2 Responsivity and quantum efficiency

     6.13.3 Parameters

     6.13.4 Noise equivalent power and specific detectivity

     6.13.5 UV detectors

     6.13.6 Visible and near-IR detectors

     6.13.7 RGB sensors

     6.13.8 IR detectors

     6.13.9 Photomultiplier tubes

6.14 Light Sources

     6.14.1 Illumination light sources

     6.14.2 Spectral lamps

     6.14.3 Light-emitting laser diodes

References

7 Commonly Used Imaging Lenses

7.1 Specifications

     7.1.1 Focal length

     7.1.2 Field of view, image size, and working distance

     7.1.3 Image quality

     7.1.4 Spectral range

     7.1.5 Transmission and illumination uniformity

     7.1.6 Magnification

     7.1.7 Depth of field

     7.1.8 Focus adjustment

     7.1.9 Zooming

     7.1.10 F-number and power-collection capability of lenses

7.2 Magnifiers

7.3 Eyepieces

     7.3.1 General description

     7.3.2 Specifications

7.4 Objectives

     7.4.1 General description

     7.4.2 Specifications

7.5 Microscopes

7.6 Telescopes

     7.6.1 Refractive telescopes

     7.6.2 Reflective telescopes

     7.6.3 Catadioptric telescopes

7.7 Binoculars

7.8 Gun Scopes

7.9 Camera Lenses

     7.9.1 F/2.8, 12-mm-focal-length lens

     7.9.2 Cellphone camera lens

     7.9.3 Focusable camera lens

     7.9.4 6X zoom camera lens

7.10 Projection Lenses

7.11 Inspection Lenses

7.12 Endoscopes

     7.12.1 Rigid endoscope

     7.12.2 Flexible endoscope

7.13 Human Eyes

     7.13.1 Photopic curve

     7.13.2 Focal length and pupil size

     7.13.3 Visual field

     7.13.4 Visual acuity

References

8 Lasers

8.1 General Comments

8.2 Working Principle

     8.2.1 Planck relation

     8.2.2 Maxwell-Boltzmann distribution

     8.2.3 Gain medium, three- and four-level systems, and population inversion

     8.2.4 Pumping sources

     8.2.5 Resonant cavity and threshold condition

     8.2.6 Standing waves

     8.2.7 Cavity stability

8.3 Laser Specifications

     8.3.1 Wavelength and tunability

     8.3.2 Power and energy: continuous, pulsed, or tunable

     8.3.3 Longitudinal modes

     8.3.4 Transverse modes

     8.3.5 Linewidth

     8.3.6 Coherent length

     8.3.7 Q-factor and Q-switching

     8.3.8 Mode-locking

8.4 Gas Lasers

     8.4.1 General description

     8.4.2 Summary

8.5 Solid State Lasers

     8.5.1 General description

     8.5.2 Summary

     8.5.3 Solid laser cavities and pumping methods

     8.5.4 Frequency doubling

8.6 Laser Diodes

     8.6.1 General description

     8.6.2 Single-TE-mode cavity structure

     8.6.3 Multi-TE-mode cavity structure

     8.6.4 Laser diode packages and modules

     8.6.5 Three special types of laser diodes and devices

8.7 Optical Fiber Lasers

8.8 Other Types of Lasers

8.9 Laser Safety

References

9 Laser Optics and Devices, and Manipulable Laser Beams

9.1 Laser Mirrors

     9.1.1 Surface qualities and coatings

     9.1.2 Mirror laser-damage threshold

9.2 Laser Lenses

     9.2.1 Surface qualities and coatings

     9.2.2 Laser lens materials

     9.2.3 Lens laser-damage threshold

9.3 Focusing or Collimating Laser Beams

     9.3.1 Geometrical optics modeling

     9.3.2 Focusing a beam: three examples

     9.3.3 Collimating laser beams

     9.3.4 Effects of lens shape and orientation

     9.3.5 Effects of aperture truncation on laser beams

9.4 Low-Power, Single-TE-Mode Laser Diode Optics

     9.4.1 Beam characteristics

     9.4.2 Lenses for collimating or focusing

     9.4.3 Spatial evolution of collimated laser diode beams

     9.4.4 Far-field pattern of collimated beams

     9.4.5 Circularization and astigmatism correction

9.5 High-Power, Wide-Stripe Laser Diode Optics

     9.5.1 Beam characteristics

     9.5.2 Collimating a wide-stripe laser diode beam

     9.5.3 Slow axis collimator

     9.5.4 Fast axis collimator

9.6 Laser Beam Shaping Optics

     9.6.1 Laser line generator

     9.6.2 Flat-top beam shaper

     9.6.3 Beam expanders

     9.6.4 Making a linear light source rectangular

9.7 Laser Devices

     9.7.1 Pigtail laser modules: coupling a single-TE-mode laser beam into a single-mode optical fiber

     9.7.2 Laser diode power stabilization

     9.7.3 Laser diode temperature stabilization

     9.7.4 Laser rangefinders

     9.7.5 Laser detection cards and viewing scopes

     9.7.6 Spatial filters

     9.7.7 Laser speckle

9.8 Opto-electrical Devices and Other Devices

     9.8.1 Basic principles

     9.8.2 Electro-optic amplitude modulators

     9.8.3 Electro-optic phase modulators

     9.8.4 Acousto-optic modulators

     9.8.5 Frequency mixing

     9.8.6 Liquid crystal devices

     9.8.7 Chopper modulators

     9.8.8 Beam-steering devices

References

10 Instruments to Characterize Laser Beams

10.1 Laser Beam Profilers

     10.1.1 Camera-based beam profilers

     10.1.2 Scanner-based beam profilers

10.2 Laser Power Meters and Energy Meters

     10.2.1 Specifications

     10.2.2 Photodetector properties and selection

10.3 Wavelength Meters

     10.3.1 General comments

     10.3.2 Fizeau wavemeters

     10.3.3 Michelson interferometer wavemeters

     10.3.4 Other wavelength measurement methods

References

11 Instruments for Optical Measurements

11.1 Wavefront Modeling

     11.1.1 General comments

     11.1.2 Aberration polynomials

     11.1.3 Zernike polynomials

     11.1.4 Wavefront polynomials

     11.1.5 Interferograms

11.2 Wavefront Analyzers

     11.2.1 Point diffraction interferometer

     11.2.2 Shack-Hartmann wavefront sensors

     11.2.3 Fizeau interferometers

     11.2.4 Shearing interferometers

     11.2.5 Twyman-Green interferometers

     11.2.6 Mach-Zehnder interferometers

11.3 Spectral Analyzers

     11.3.1 Monochromators

     11.3.2 Scanning Fabry-Perot interferometers

11.4 Other Optical Instruments

     11.4.1 Measuring microscopes

     11.4.2 Autocollimators

     11.4.3 Radiometers and photometers

References

12 Computer-Aided Optical Modeling

12.1 General Comments

12.2 Commercially Available Optical Design Software

     12.2.1 CODE V

     12.2.2 OpticStudio (Zemax)

     12.2.3 Other types of optical software

12.3 Sequential Raytracing Modeling

     12.3.1 General comments

     12.3.2 Set optical parameters

     12.3.3 Modeling a single lens

     12.3.4 Modeling a mirror

     12.3.5 Modeling coatings 313

     12.3.6 Modeling a multi-element lens

12.4 Non-sequential Raytracing Modeling

     12.4.1 General comments

     12.4.2 Modeling a light source

     12.4.3 Modeling a detector

     12.4.4 Modeling a lens

     12.4.5 Detector viewer and raytracing

     12.4.6 Modeling a mirror

     12.4.7 Modeling a dispersion prism

     12.4.8 Modeling a cube beamsplitter with a beamsplitting coating

12.5 Physical Optics Modeling

     12.5.1 Modeling a laser diode beam

     12.5.2 Modeling a laser beam propagating through an equi-convex spherical lens

     12.5.3 Modeling a laser beam propagating through an aspheric laser diode lens

References

13 Computer-Aided Optical Design

13.1 Optical Engineering and Design

     13.1.1 Optical engineering versus electrical engineering

     13.1.2 The unique nature of optical design

     13.1.3 Design process: merit function

     13.1.4 Design process: optimization

13.2 Design a Focusing Single Lens

     13.2.1 Set a Lens Data box

     13.2.2 Construct a merit function

     13.2.3 Optimize

     13.2.4 Use aspheric surfaces

13.3 Design a Focusing Doublet

     13.3.1 Set a Lens Data box

     13.3.2 Construct a merit function and optimize

13.4 Design a Simple Eyepiece

     13.4.1 Set system parameters

     13.4.2 Set a Lens Data box

     13.4.3 Construct a merit function

     13.4.4 Optimize

     13.4.5 Design results

     13.4.6 Design strategies

13.5 Design a Simple Microscope Objective

     13.5.1 Set system parameters

     13.5.2 Set a Lens Data box

     13.5.3 Construct a merit function

     13.5.4 Optimization and design results

13.6 Build a Polygon

14 Lens Fabrication, Tolerances, Procurement, Inspection, and Mounting

14.1 Optical Specifications and Standards

14.2 Lens Fabrication Methods

     14.2.1 Spindle grinding and polishing

     14.2.2 Diamond turning

     14.2.3 Molding

14.3 Fabrication Tolerances

     14.3.1 Tolerances of the surface curvature radius and surface sag difference

     14.3.2 Decenter, tilt, and wedge between the two surfaces of a lens

     14.3.3 Optical fabrication tolerance chart

14.4 Purchasing Optical Components

     14.4.1 Off-the-shelf optical component vendors

     14.4.2 Custom component vendors

     14.4.3 Custom component price estimation

     14.4.4 Lens drawings and data sheet for custom components

     14.4.5 Review inspection report

     14.4.6 Incoming inspection

14.5 Measuring the Surface Radius of Curvature, Surface Quality, and Lens Physical Size

     14.5.1 Profilometers

     14.5.2 Test plates

     14.5.3 Interferometer methods

     14.5.4 Test aspheric surfaces

     14.5.5 Measuring surface quality

     14.5.6 Measuring physical size

14.6 Methods for Measuring the Lens Focal Length

     14.6.1 Transverse magnification method

     14.6.2 Nodal slide method

     14.6.3 Measuring the focal length of a negative lens

14.7 Methods for Measuring the Image Resolution of a Lens

     14.7.1 USAF resolution test chart

     14.7.2 Siemens star chart

     14.7.3 Slant edge

14.8 Principles of Mounting Lenses

     14.8.1 Passive mounting

     14.8.2 Total indicator of runout

     14.8.3 Active mounting

14.9 Techniques for Mounting Lenses

     14.9.1 Mounting a laser diode beam-collimating lens

     14.9.2 Passive method of centering a lens

     14.9.3 Setting the axial spacing between two lenses

     14.9.4 Fixing the lens position

     14.9.5 Aligning a lens to a cell

14.10 Handling and Cleaning Optical Components

     14.10.1 Handling components

     14.10.2 Cleaning components

References

Preface

Optical engineering is increasingly used in industrial, scientific, medical, and military applications, among others. Engineers and scientists need to have certain knowledge in order to effectively apply optics to their projects; however, most of them did not major in optical engineering. Their busy schedules do not allow them to spend a lot time to study the details of optical engineering. Their interests are often limited to quickly gaining the most basic concepts and identifying the right optical components, devices, instruments, and approaches for their applications. What they need is an information source that can promptly provide them the very practical knowledge about a specific part of optical engineering.

In the past several decades, about ten notable books on optical engineering have been published. Several recently published books are available, e.g., Refs. 1-5. The first three approach the topic in a gradual way with detailed explanations and are excellent textbooks for students majoring in optical engineering, as well as for engineers and scientists who have enough time and interest to dig deep into the subject. Fischer covers optical system design with practical design examples and also addresses basic optics and optical components. Smith is a comprehensive book that covers many technical details about classical optical engineering. Both Fischer and Smith are great references for optical engineers and scientists. However, none of these books discuss lasers, laser optics and devices, and fiber optics, even though lasers and optical fibers are now conventional optical components. Smith devotes a section to optical fibers but treats optical fiber as a bulk glass waveguide; most of the important features of optical fibers are not covered.

Basic Optical Engineering for Engineers and Scientists introduces the very practical parts of optical engineering to address the needs of those engineers and scientists who are not specialized in the subject but need to quickly learn something about it for their projects. The text briefly introduces the most basic optics, but most of it describes various optical components, optical devices and systems, lasers, laser optics and devices, optical fibers, optoelectrical devices, optical designs, and optical assemblies. The performance specifications of some optical components that represent current technologies are also provided.

This book tries to avoid detailed manual numerical calculations and raytracings because these techniques are complex, time consuming, and often inaccurate. Instead, computers and optical software are used to perform these tasks because computers and optical software are widely available and the results provided by programs are much more accurate than the results obtained manually. There are no proofs or problem-solving exercises. These features are intended to let readers find the content relevant to their interests and get the results they need. This book tries to cover most areas of modern optical engineering but not in depth.

Haiyin Sun
December 2018