July 2003 Chuck DiMarzio, Northeastern University 10351a-1-1 ECEG105 & ECEU646 Optics for Engineers Course Notes Part 1: Introduction Prof. Charles A. DiMarzio Northeastern University Fall 2003

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-2 Lecture 1 Overview Administrivia –Course Layout –Grading –Syllabus Introduction –Why Optics? –A bit of history –Our Approach

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-3 Why Optics? Absorption Spectrum of the Atmosphere Absorption Spectrum of Liquid Water Index of Refraction 1nm 1m1m 1m1m 1mm1m 1km 1nm 1m1m 1m1km1mm from Jackson

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-4 Earthlight

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-5 A Bit of History “...and the foot of it of brass, of the lookingglasses of the women assembling,” (Exodus 38:8) Rectilinear Propagation (Euclid) Shortest Path (Almost Right!) (Hero of Alexandria) Plane of Incidence Curved Mirrors (Al Hazen) Empirical Law of Refraction (Snell) Light as Pressure Wave (Descartes) Law of Least Time (Fermat) v<c, & Two Kinds of Light (Huygens) Corpuscles, Ether (Newton) Wave Theory (Longitudinal) (Fresnel) Transverse Wave, Polarization Interference (Young) Light & Magnetism (Faraday) EM Theory (Maxwell) Rejectionof Ether, Early QM (Poincare, Einstein)

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-6 More Recent History Laser (Maiman) Quantum Mechanics Optical Fiber (Lamm) SM Fiber (Hicks) HeNe (Javan) Polaroid Sheets (Land) Phase Contrast (Zernicke) Holography (Gabor) Optical Maser (Schalow, Townes) GaAs (4 Groups) CO 2 (Patel) FEL (Madey) Hubble Telescope Speed/Light (Michaelson) Spont. Emission (Einstein) Many New Lasers Erbium Fiber Amp Commercial Fiber Link (Chicago)

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-7 The First Laser? Malibu, 1960 The First Laser News Photo of the First Laser ?

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-8 Some Everyday Applications Illumination Signaling Cameras; Film and Electronic Bar-Code Reader Surveying and Rangefinding Microscopy Astronomy

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-9 My Research Interests Biological and Medical Imaging –Acousto-Photonic Imaging (DOT and Ultrasound) –Optical Quadrature Microscopy Landmine Detection –Laser-Induced Acoustic Mine Detection –Microwave-Enhanced Infrared Thermography Environmental Sensing –Optical Magnetic Field Sensor –Underwater Imaging with a Laser Line Scanner –Hyperspectral Imaging Laboratory Experiments

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-10 Some Other Applications (1) Communication –Lasers and Fast Modulation –Fibers for Propagation –Fast Detectors –Dense Wavelength Diversity Multiplexing –Free-Space Propagation (Not Much) Optical Disk Memory –Lasers, Detectors –Diffraction Limited Optics

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-11 Some Other Applications (2) Photo Lithography for Integrated Circuits –Short Wavelength Sources –Diffraction Limited Optics Adaptive Optical Imaging –Non-Linear Materials or Mechanical Actuators Velocimetry and Vibrometry –Coherent Detection, Coherent Sources

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-12 Some Other Applications (3) Hyperspectral Imaging –Dispersive Elements –Large Detector Arrays –Fast Processing Medical Treatment –Delivery –Dosimetry

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-13 Some Recent Advances Laser Tweezers Optical Cooling Squeezed States Entangled-States Fiber-Based Sensors Optical Micro-Electro-Mechanical Systems

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-14 Some Everyday Concepts (1) Specular and Diffuse Reflection Refraction Specular DiffuseRetro

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-15 Some Everyday Concepts (2) Imaging Wavefronts Rays The Observer Object Image Object Image

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-16 High-School Optics F F’ Object Image

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-17 Our Approach Maxwell’s Equations Wave Equation Scalar Wave Equation Geometric Optics Polarization Interference Diffraction Radiometry Non-Linear Optics stopped 12 Sep 03

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-18 Maxwell’s Equations Constitutive Parameters Faraday’s Equation Ampere’s Equation Gauss’s Equations

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-19 Maxwell’s Equations Source-Free Region –No  or J Isotropic Medium –E Parallel to D Harmonic Functions –No Nonlinear Effects

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-20 Getting to the Wave Equation HB E D Almost everything interesting is here

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-21 The Goodies are in Epsilon HB ED HB ED More on this later in the course.

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-22 The General Problem Goals –Solve Maxwell’s Equations –Satisfy Boundary Conditions Approaches –Special Cases (eg. Plane, Spherical, etc.) –Approximations Circuit Theory (  >>D) Wave Theory (  D) Geometric Optics (  <<D)

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-23 Steps to Geometric Optics Maxwell’s Equations Vector Wave Equation Scalar Wave Equation General Wave Solution Eikonel Equation (zero-wavelength approximation)

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-24 Vector Wave Equation H B ED Linear Medium

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-25 Scalar Wave Equation H B ED Linear, Isotropic Medium (Two States of Polarization)

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-26 Eikonel Equation (1) Scalar Wave Equation Proposed Solution Left Side Right Side Solution

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-27 Eikonel Equation (2) From Previous Page Zero Wavelength Approximation (with derivatives of a sufficiently small) Optical Path Length Along a Ray

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-28 Eikonel Equation (3) L(r)=Constant Defines Wavefronts –Thus, Wavefronts Are Perpendicular to Rays Define Optical Path Length –Compare Travel Time to Light in Vacuum n1n1 n2n2 n3n3 n5n5 n4n4

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-29 Optical Path Concept Not to Be Confused with Image Location OPL Physical Distance Image Distance

July 2003 Chuck DiMarzio, Northeastern University 10351a-1-30 Fermat’s Principle Where Does Ray Go? –Minimize Optical Path Imaging: –Many Minimal Paths