July © Chuck DiMarzio, Northeastern University a-1 ECEG105/ECEU646 Optics for Engine6ers Course Notes Part 1: Introduction Prof. Charles A. DiMarzio Northeastern University Fall 2008 Sep 2008

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

July © Chuck DiMarzio, Northeastern University a-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 Sep 2008

July © Chuck DiMarzio, Northeastern University a-4 Earthlight

July © Chuck DiMarzio, Northeastern University a-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) Sep

July © Chuck DiMarzio, Northeastern University a-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) Sep 2008

July © Chuck DiMarzio, Northeastern University a-7 The First Laser? Malibu, 1960 The First Laser News Photo of the First Laser ? "Laser, inter eximia naturae dona numeratum plurimis compositionibus inseritur*" "The laser is numbered among the most miraculous gifts of nature and lends itself to a variety of applications." Pliny, Natural History XXII, 49 Jan 2005

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

July © Chuck DiMarzio, Northeastern University a-9 My Research Interests Biological and Medical Imaging –Multi-Modal Microscopy –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 Jul 2007

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

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

July © Chuck DiMarzio, Northeastern University a-14 Some Everyday Concepts (1) Specular and Diffuse Reflection Refraction and Transmission Specular DiffuseRetro Dec 2004

July © Chuck DiMarzio, Northeastern University a-15 Example Interactions Slab Transmission Slab Absorption and Scattering Mostly Diffuse Reflection Specular with some Diffuse Reflection Dec 2004

July © Chuck DiMarzio, Northeastern University a-16 Some Everyday Concepts (2) Imaging Wavefronts Rays The Observer Object Image Object Image Sep 2007

July © Chuck DiMarzio, Northeastern University a-17 Imaging Jul 2007 Sep 2007 Near Card Demonstrates Camera is Focused Closer than Lens

July © Chuck DiMarzio, Northeastern University a-18 High-School Optics F F’ Object Image Stopped Here 4 Jan 05

July © Chuck DiMarzio, Northeastern University a-19 Our Approach Maxwell’s Equations Wave Equation Scalar Wave Equation Geometric Optics Polarization Interference Diffraction Radiometry stopped 12 Sep 03

July © Chuck DiMarzio, Northeastern University a-20 Maxwell’s Equations Jul 2007

July © Chuck DiMarzio, Northeastern University a-21 Maxwell’s Equations Source-Free Region –No  or J Isotropic Medium –E Parallel to D Harmonic Functions –No Nonlinear Effects

July © Chuck DiMarzio, Northeastern University a-22 Getting to the Wave Equation HB E D Almost everything interesting is here

July © Chuck DiMarzio, Northeastern University a-23 The Goodies are in Epsilon HB ED HB ED More on this later in the course.

July © Chuck DiMarzio, Northeastern University a-24 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 © Chuck DiMarzio, Northeastern University a-25 Steps to Geometric Optics Maxwell’s Equations Vector Wave Equation Scalar Wave Equation General Wave Solution Eikonel Equation (zero-wavelength approximation)

July © Chuck DiMarzio, Northeastern University a-26 Vector Wave Equation Jan 2005 H B ED Sep

July © Chuck DiMarzio, Northeastern University a-27 Scalar Wave Equation H B ED Linear, Isotropic Medium (Two States of Polarization) Sep 2007

July © Chuck DiMarzio, Northeastern University a-28 Eikonel Equation (1)

July © Chuck DiMarzio, Northeastern University a-29 Eikonel Equation (2) 0 22 

July © Chuck DiMarzio, Northeastern University a-30 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 © Chuck DiMarzio, Northeastern University a-31 Plane Waves Scalar Wave Equation General Solution Plane-Wave Solution Plane-Wave in z Direction Dec 2004

July © Chuck DiMarzio, Northeastern University a-32 Optical Path Concept Not to Be Confused with Image Location Physical Distance Image Distance OPL

July © Chuck DiMarzio, Northeastern University a-33 Fermat’s Principle Where Does Ray Go? –Minimize Optical Path Imaging: –Many Minimal Paths

July © Chuck DiMarzio, Northeastern University a-34 Jan 2005

July © Chuck DiMarzio, Northeastern University a-35 Dec 2004 Stopped Here Thu 6 Jan 05