March Chuck DiMarzio, Northeastern University ECE-1466 Modern Optics Course Notes Part 1 Prof. Charles A. DiMarzio Northeastern University Spring 2002

March Chuck DiMarzio, Northeastern University ECE1466: Modern Optics Instructor: Chuck DiMarzio Office Hours: Thu 2-4 or by appointment ece.neu.edu Web: Check frequently for new material – Course Mailing List: Use for general questions –Send me and I will add your name.

March Chuck DiMarzio, Northeastern University Lecture 1 Overview Introduction –Why Optics? –A bit of history –Motivational Example; Microscope Administrivia –Course Layout –Grading –Syllabus

March Chuck DiMarzio, Northeastern University 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

March Chuck DiMarzio, Northeastern University Earthlight

March Chuck DiMarzio, Northeastern University 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)

March Chuck DiMarzio, Northeastern University 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)

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

March Chuck DiMarzio, Northeastern University 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

March Chuck DiMarzio, Northeastern University 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

March Chuck DiMarzio, Northeastern University 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

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

March Chuck DiMarzio, Northeastern University Some Recent Advances Laser Tweezers Optical Cooling Entangled-States Fiber-Based Sensors Optical Micro-Electro-Mechanical Systems

March Chuck DiMarzio, Northeastern University Motivation: Designing a New Microscope It’s Not Just About Resolution –Resolution Limited by Diffraction It’s About What Is Measured –Transmission, Reflection, Phase, Fluorescence, Polarization, Non-Linear Properties And About How Data Are Processed –Registration, Deconvolution, Tomography, Parameter Estimation And About Measuring Everything at Once

March Chuck DiMarzio, Northeastern University Contrast Features Material Properties –Wavespeed –Attenuation –Birefringence –Non-Linearity Composition: What are the materials? Quantitative Measurements: How much of each? Structure: How they are arranged? – Boundaries –Shapes

March Chuck DiMarzio, Northeastern University A Couple of Rules Frequency and Wavelength – =c where is frequency, is wavelength –c is the speed of light. Photon Energy – E = h where h is Planck’s constant Materials Absorb and Emit Photons with Corresponding Changes in Energy

March Chuck DiMarzio, Northeastern University Some Material Properties Absorption Energy EmissionFluorescence 2-photon

March Chuck DiMarzio, Northeastern University D Fusion Microscope DIC QTM TPLSM LSCM RCM

March Chuck DiMarzio, Northeastern University Interference and Quadrature Microscopy QWP Object CCD Laser Source

March Chuck DiMarzio, Northeastern University Mouse Embryos with DIC Image by Carsta Cielich in Carol Warner’s Laboratory at Northeastern University 4-Cell Embryo 2-Cell 1-Cell Multi-Cell Embryo  m Fragmented Cell Compacted Embryo

March Chuck DiMarzio, Northeastern University Mouse Oocyte with QTM 3993.jpg jpg jpg Unwrapped Phase Phase Amplitude

March Chuck DiMarzio, Northeastern University Reflectance Confocal; VivaScope imaging in vivo Some 3D Scanning Microscopes thanks to Badri Roysam, RPI Fluorescence Confocal Two-Photon Microscope pxl

March Chuck DiMarzio, Northeastern University What Does Each Mode Contribute? DIC: –2-D Structure QTM: – 2-D Phase, 3-D Index and Absorption RCM: – 3-D Structure LSCM: – 3-D Composition TPLSM: – 3-D Composition (Endogenous Fluorophores)

March Chuck DiMarzio, Northeastern University Why Use This Example? Important Application Area Current Interest at Northeastern Coverage of Important Topics –Geometric Optics –Diffraction –Interference –Polarization –Non-Linear Optics –Lasers –Signals and Noise

March Chuck DiMarzio, Northeastern University Some Everyday Concepts (1) Specular and Diffuse Reflection Refraction Specular DiffuseRetro

March Chuck DiMarzio, Northeastern University Some Everyday Concepts (2) Imaging Wavefronts

March Chuck DiMarzio, Northeastern University High-School Optics F F’ Object Image

March Chuck DiMarzio, Northeastern University Basic Geometric Optics Reflection and Refraction Imaging –Real and Virtual –Image Location; Conjugate Planes –Magnification Transverse, Angular, Longitudinal Reflecting Optics (Not much in this course) Refracting Optics

March Chuck DiMarzio, Northeastern University Reflection  

March Chuck DiMarzio, Northeastern University Plane of Incidence ’’’’  Contains Normal Contains Incident Ray And Thus Contains Refracted Ray Is the Plane Shown in the Drawing Angles –Defined from Normal

March Chuck DiMarzio, Northeastern University Imaging First, Assume a Point Object –Spherical Wavefronts and Radial Rays Define Object Location –Find Image Location –Real or Virtual? Next Assume an Extended Object –Compute Magnification Transverse, Longitudinal, Angular

March Chuck DiMarzio, Northeastern University Where Are We Going? Geometric Optics –Reflection –Refraction The Thin Lens –Multiple Surfaces –(From Matrix Optics) Principal Planes Effective Thin Lens –Stops Field Aperture –Aberrations Ending with a word about ray tracing and optical design.

March Chuck DiMarzio, Northeastern University The Plane Mirror (1) Point Object Extended Object   AA’ -s’ s  AA’ BB’ h x x’

March Chuck DiMarzio, Northeastern University The Plane Mirror (2) dx’ dy’ds’ ds dy dx x’=x m=x’/x=1 Transverse Magnification ds’=-ds m z =ds’/ds=-1 Longitudinal Magnification  ’’=  m  =  ’’/  =1 Angular Magnification Image is Virtual (Dotted lines converge) Erect (m>0), Perverted (can not rotate to object) but not distorted (|m|=|m z |) (refer to picture on left side of previous page)

March Chuck DiMarzio, Northeastern University Refracting Surfaces (1) Snell’s Law ’’’’  n n’ Angle of Incidence Angle of Refraction Air to Water Air to Glass Air to ZnSe (10  m) Air to Ge (10  m)

March Chuck DiMarzio, Northeastern University Refracting Surfaces (2) Snell’s Law ’’  n n’ Angle of Incidence Angle of Refraction Water to Air Glass to Air ZnSe to Air (10  m) Ge to Air(10  m) Critical Angle

March Chuck DiMarzio, Northeastern University Sign Definitions Object Distance, s –Positive to Left Image Distance, s’ –For Refraction Positive to Right –For Reflection Positive to Left Notation –Capital Letter; Point –Lower Case; Distance –(Almost Always) s s’ s A A’ B B’ F F’ f

March Chuck DiMarzio, Northeastern University Real and Virtual Images Real Image –Rays Converge –Can Image on Paper –Solid Lines in Notes Virtual Image –Extended Rays Converge –Dotted-Lines in notes

March Chuck DiMarzio, Northeastern University The Thin Lens (1)

March Chuck DiMarzio, Northeastern University The Thin Lens (2) Front Focal LengthBack Focal Length ff’

March Chuck DiMarzio, Northeastern University Special Case: Thin Lens in Air Lens Makers Equation with d = 0Lens Equation ff’

March Chuck DiMarzio, Northeastern University Imaging Systems HH’VV’ D’Df s s’ f’ B B’ w w’ s, s’ are object and image distances w, w’ are working distances

March Chuck DiMarzio, Northeastern University Principal Planes with Bending p1, Power of Front Surface, /cm. Locations: V, V',H,H' P 1 +P 2 =0.1/cm, z 12 =0.5 cm, n=1.5 HH’=VV’/3 holds, except for extreme meniscus lenses. H, H’ in lens from plano-convex to convex-plano. Mensicus lenses not common.

March Chuck DiMarzio, Northeastern University Bending an IR Lens (Ge: n=4) p1, Power of Front Surface, /cm. Locations: V, V',H,H' P 1 +P 2 =0.1/cm, z 12 =0.5 cm, n=4 HH’=VV’X3/4 for n=4, over a wide range of bending. Meniscus lenses are more common in the IR because of the high indices of refraction, as we will see later.

March Chuck DiMarzio, Northeastern University Some Optical Failures f’ f Right Focal Length, Wrong Principal Planes For the Application Meniscus Lens for Infrared Detector