Lecture 16 — March 9, 2021 1 Outline 2 Diffraction
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Gustav Robert Kirchhoff War Der Sohn Eines Landrichters
Akademischer Werdegang *12.03.1824 in Königsberg (heute: Kaliningrad) Besuch des Kneiphöschen Gymnasiums in Königsberg ab 1842 Studium der Mathematik und Physik an der Universität Königsberg 1847 Promotion in Berlin 1850 Berufung zum außerordentlichen Professor nach Breslau (Polen) 1854 Professor für Physik an der Universität Heidelberg 1874 – 1886 Professor für mathematische Physik in Berlin 1876 Cothenius – Medaille der Leopoldina als Auszeichnung für [1] wissenschaftliches Arbeiten † 17.10.1887 in Berlin Gustav Robert Kirchhoff war der Sohn eines Landrichters. Während des Studiums in seiner Heimatstadt wurde er u. a. von den Professoren F.E. Neumann und F. J. Richelot gelehrt. Im Physikseminar von Neumann verfasste Kirchhoff mit 21 Jahren seine erste Arbeit über den Durchgang der Elektrizität durch Platten. Während der Promotions- und Habilitationsphase an der Universität Berlin entwickelte sich eine Freundschaft mit dem Universalgenie H. Helmholtz. Kirchhoff folgte schließlich der Berufung zum außerordentlichen Professor nach Breslau, wo er R. W. Bunsen, den Erfinder des Bunsenbrenners kennen lernte. Dieser wechselte zur Universität nach Heidelberg, worauf ihm Kirchhoff folgte. Gemeinsam veröffentlichten sie zahlreiche Schriften und entdeckten, wie verschiedene chemische Elemente die Flamme eines Gasbrenners färben. Sie prägten die Spektralanalyse als physikalische Analysemethode und konnten mit ihrer Hilfe eine Erklärung der Frauenhoferlinie finden. Außerdem verzeichneten sie die Entdeckung der Elemente Caesium und Rubidium. Des Weiteren entstand bei Experimenten der Spektralanalyse der Kirchhoffsche Strahlungssatz. Kirchhoffs und Bunsens erster Spektralapparat [2] Kirchhoff arbeitete auch an der Plattentheorie. Der Piola-Kirchhoff-Spannungstensor, die Kirchhoff-Love- Hypothese und die sogenannten Kirchhoff-Platten erinnern daran. 1857 heiratete er Clara Richelot, die Tochter seines Professors für Mathematik. Gemeinsam bekamen sie vier Kinder und führten eine glückliche Ehe. -
A Numerical Study of Resolution and Contrast in Soft X-Ray Contact Microscopy
Journal of Microscopy, Vol. 191, Pt 2, August 1998, pp. 159–169. Received 24 April 1997; accepted 12 September 1997 A numerical study of resolution and contrast in soft X-ray contact microscopy Y.WANG&C.JACOBSEN Department of Physics, State University of New York at Stony Brook, Stony Brook, NY 11794-3800, U.S.A. Key words. Contrast, photoresists, resolution, soft X-ray microscopy. Summary In this paper we consider the nature of contact X-ray micrographs recorded on photoresists, and the limitations We consider the case of soft X-ray contact microscopy using on image resolution imposed by photon statistics, diffrac- a laser-produced plasma. We model the effects of sample tion and by the process of developing the photoresist. and resist absorption and diffraction as well as the process Numerical simulations corresponding to typical experimen- of isotropic development of the photoresist. Our results tal conditions suggest that it is difficult to reliably interpret indicate that the micrograph resolution depends heavily on details below the 40 nm level by these techniques as they the exposure and the sample-to-resist distance. In addition, now are frequently practised. the contrast of small features depends crucially on the development procedure to the point where information on such features may be destroyed by excessive development. 2. X-ray contact microradiography These issues must be kept in mind when interpreting contact microradiographs of high resolution, low contrast There is a long history of research in which X-ray objects such as biological structures. radiographs have been viewed with optical microscopes to study submillimetre structures (Gorby, 1913). -
The Green-Function Transform and Wave Propagation
1 The Green-function transform and wave propagation Colin J. R. Sheppard,1 S. S. Kou2 and J. Lin2 1Department of Nanophysics, Istituto Italiano di Tecnologia, Genova 16163, Italy 2School of Physics, University of Melbourne, Victoria 3010, Australia *Corresponding author: [email protected] PACS: 0230Nw, 4120Jb, 4225Bs, 4225Fx, 4230Kq, 4320Bi Abstract: Fourier methods well known in signal processing are applied to three- dimensional wave propagation problems. The Fourier transform of the Green function, when written explicitly in terms of a real-valued spatial frequency, consists of homogeneous and inhomogeneous components. Both parts are necessary to result in a pure out-going wave that satisfies causality. The homogeneous component consists only of propagating waves, but the inhomogeneous component contains both evanescent and propagating terms. Thus we make a distinction between inhomogenous waves and evanescent waves. The evanescent component is completely contained in the region of the inhomogeneous component outside the k-space sphere. Further, propagating waves in the Weyl expansion contain both homogeneous and inhomogeneous components. The connection between the Whittaker and Weyl expansions is discussed. A list of relevant spherically symmetric Fourier transforms is given. 2 1. Introduction In an impressive recent paper, Schmalz et al. presented a rigorous derivation of the general Green function of the Helmholtz equation based on three-dimensional (3D) Fourier transformation, and then found a unique solution for the case of a source (Schmalz, Schmalz et al. 2010). Their approach is based on the use of generalized functions and the causal nature of the out-going Green function. Actually, the basic principle of their method was described many years ago by Dirac (Dirac 1981), but has not been widely adopted. -
Approximate Separability of Green's Function for High Frequency
APPROXIMATE SEPARABILITY OF GREEN'S FUNCTION FOR HIGH FREQUENCY HELMHOLTZ EQUATIONS BJORN¨ ENGQUIST AND HONGKAI ZHAO Abstract. Approximate separable representations of Green's functions for differential operators is a basic and an important aspect in the analysis of differential equations and in the development of efficient numerical algorithms for solving them. Being able to approx- imate a Green's function as a sum with few separable terms is equivalent to the existence of low rank approximation of corresponding discretized system. This property can be explored for matrix compression and efficient numerical algorithms. Green's functions for coercive elliptic differential operators in divergence form have been shown to be highly separable and low rank approximation for their discretized systems has been utilized to develop efficient numerical algorithms. The case of Helmholtz equation in the high fre- quency limit is more challenging both mathematically and numerically. In this work, we develop a new approach to study approximate separability for the Green's function of Helmholtz equation in the high frequency limit based on an explicit characterization of the relation between two Green's functions and a tight dimension estimate for the best linear subspace approximating a set of almost orthogonal vectors. We derive both lower bounds and upper bounds and show their sharpness for cases that are commonly used in practice. 1. Introduction Given a linear differential operator, denoted by L, the Green's function, denoted by G(x; y), is defined as the fundamental solution in a domain Ω ⊆ Rn to the partial differ- ential equation 8 n < LxG(x; y) = δ(x − y); x; y 2 Ω ⊆ R (1) : with boundary condition or condition at infinity; where δ(x − y) is the Dirac delta function denoting an impulse source point at y. -
Waves and Imaging Class Notes - 18.325
Waves and Imaging Class notes - 18.325 Laurent Demanet Draft December 20, 2016 2 Preface In the margins of this text we use • the symbol (!) to draw attention when a physical assumption or sim- plification is made; and • the symbol ($) to draw attention when a mathematical fact is stated without proof. Thanks are extended to the following people for discussions, suggestions, and contributions to early drafts: William Symes, Thibaut Lienart, Nicholas Maxwell, Pierre-David Letourneau, Russell Hewett, and Vincent Jugnon. These notes are accompanied by computer exercises in Python, that show how to code the adjoint-state method in 1D, in a step-by-step fash- ion, from scratch. They are provided by Russell Hewett, as part of our software platform, the Python Seismic Imaging Toolbox (PySIT), available at http://pysit.org. 3 4 Contents 1 Wave equations 9 1.1 Physical models . .9 1.1.1 Acoustic waves . .9 1.1.2 Elastic waves . 13 1.1.3 Electromagnetic waves . 17 1.2 Special solutions . 19 1.2.1 Plane waves, dispersion relations . 19 1.2.2 Traveling waves, characteristic equations . 24 1.2.3 Spherical waves, Green's functions . 29 1.2.4 The Helmholtz equation . 34 1.2.5 Reflected waves . 35 1.3 Exercises . 39 2 Geometrical optics 45 2.1 Traveltimes and Green's functions . 45 2.2 Rays . 49 2.3 Amplitudes . 52 2.4 Caustics . 54 2.5 Exercises . 55 3 Scattering series 59 3.1 Perturbations and Born series . 60 3.2 Convergence of the Born series (math) . 63 3.3 Convergence of the Born series (physics) . -
Summary of Wave Optics Light Propagates in Form of Waves Wave
Summary of Wave Optics light propagates in form of waves wave equation in its simplest form is linear, which gives rise to superposition and separation of time and space dependence (interference, diffraction) waves are characterized by wavelength and frequency propagation through media is characterized by refractive index n, which describes the change in phase velocity media with refractive index n alter velocity, wavelength and wavenumber but not frequency lenses alter the curvature of wavefronts Optoelectronic, 2007 – p.1/25 Syllabus 1. Introduction to modern photonics (Feb. 26), 2. Ray optics (lens, mirrors, prisms, et al.) (Mar. 7, 12, 14, 19), 3. Wave optics (plane waves and interference) (Mar. 26, 28), 4. Beam optics (Gaussian beam and resonators) (Apr. 9, 11, 16), 5. Electromagnetic optics (reflection and refraction) (Apr. 18, 23, 25), 6. Fourier optics (diffraction and holography) (Apr. 30, May 2), Midterm (May 7-th), 7. Crystal optics (birefringence and LCDs) (May 9, 14), 8. Waveguide optics (waveguides and optical fibers) (May 16, 21), 9. Photon optics (light quanta and atoms) (May 23, 28), 10. Laser optics (spontaneous and stimulated emissions) (May 30, June 4), 11. Semiconductor optics (LEDs and LDs) (June 6), 12. Nonlinear optics (June 18), 13. Quantum optics (June 20), Final exam (June 27), 14. Semester oral report (July 4), Optoelectronic, 2007 – p.2/25 Paraxial wave approximation paraxial wave = wavefronts normals are paraxial rays U(r) = A(r)exp(−ikz), A(r) slowly varying with at a distance of λ, paraxial Helmholtz equation -
The Second Physicist on the History of Theoretical Physics in Germany
springer.com Physics : Theoretical, Mathematical and Computational Physics Jungnickel, Christa, McCormmach, Russell The Second Physicist On the History of Theoretical Physics in Germany Explores the rise of theoretical physics in 19th century Germany Shows how physics developed within German universities Characterizes the work of theoretical physics This book explores the rise of theoretical physics in 19th century Germany. The authors show how the junior second physicist in German universities over time became the theoretical physicist, of equal standing to the experimental physicist. Gustav Kirchhoff, Hermann von Helmholtz, and Max Planck are among the great German theoretical physicists whose work and career are examined in this book. Physics was then the only natural science in whichtheoreticalwork developed into a major teaching and research specialty in its own right. Readers will discover how German physicists arrived at a well-defined field of theoretical physics with well understood and generally accepted goals and needs. The authors explain the Springer nature of theworkof theoretical physics with many examples, taking care always to locate the 1st ed. 2017, XXXI, 460 p. research within the workplace. The book is a revised and shortened version ofIntellectual 1st 15 illus. Mastery of Nature: Theoretical Physics from Ohm to Einstein, a two-volume work by the same edition authors. This new edition represents a reformulation of the larger work. It retains what is most important in the original work, while including new material, -
Fourier Optics
Fourier optics 15-463, 15-663, 15-862 Computational Photography http://graphics.cs.cmu.edu/courses/15-463 Fall 2017, Lecture 28 Course announcements • Any questions about homework 6? • Extra office hours today, 3-5pm. • Make sure to take the three surveys: 1) faculty course evaluation 2) TA evaluation survey 3) end-of-semester class survey • Monday are project presentations - Do you prefer 3 minutes or 6 minutes per person? - Will post more details on Piazza. - Also please return cameras on Monday! Overview of today’s lecture • The scalar wave equation. • Basic waves and coherence. • The plane wave spectrum. • Fraunhofer diffraction and transmission. • Fresnel lenses. • Fraunhofer diffraction and reflection. Slide credits Some of these slides were directly adapted from: • Anat Levin (Technion). Scalar wave equation Simplifying the EM equations Scalar wave equation: • Homogeneous and source-free medium • No polarization 1 휕2 훻2 − 푢 푟, 푡 = 0 푐2 휕푡2 speed of light in medium Simplifying the EM equations Helmholtz equation: • Either assume perfectly monochromatic light at wavelength λ • Or assume different wavelengths independent of each other 훻2 + 푘2 ψ 푟 = 0 2휋푐 −푗 푡 푢 푟, 푡 = 푅푒 ψ 푟 푒 휆 what is this? ψ 푟 = 퐴 푟 푒푗휑 푟 Simplifying the EM equations Helmholtz equation: • Either assume perfectly monochromatic light at wavelength λ • Or assume different wavelengths independent of each other 훻2 + 푘2 ψ 푟 = 0 Wave is a sinusoid at frequency 2휋/휆: 2휋푐 −푗 푡 푢 푟, 푡 = 푅푒 ψ 푟 푒 휆 ψ 푟 = 퐴 푟 푒푗휑 푟 what is this? Simplifying the EM equations Helmholtz equation: -
Convolution Quadrature for the Wave Equation with Impedance Boundary Conditions
Convolution Quadrature for the Wave Equation with Impedance Boundary Conditions a b, S.A. Sauter , M. Schanz ∗ aInstitut f¨urMathematik, University Zurich, Winterthurerstrasse 190, CH-8057 Z¨urich, Switzerland, e-mail: [email protected] bInstitute of Applied Mechanics, Graz University of Technology, 8010 Graz, Austria, e-mail: [email protected] Abstract We consider the numerical solution of the wave equation with impedance bound- ary conditions and start from a boundary integral formulation for its discretiza- tion. We develop the generalized convolution quadrature (gCQ) to solve the arising acoustic retarded potential integral equation for this impedance prob- lem. For the special case of scattering from a spherical object, we derive rep- resentations of analytic solutions which allow to investigate the effect of the impedance coefficient on the acoustic pressure analytically. We have performed systematic numerical experiments to study the convergence rates as well as the sensitivity of the acoustic pressure from the impedance coefficients. Finally, we apply this method to simulate the acoustic pressure in a building with a fairly complicated geometry and to study the influence of the impedance coefficient also in this situation. Keywords: generalized Convolution quadrature, impedance boundary condition, boundary integral equation, time domain, retarded potentials 1. Introduction The efficient and reliable simulation of scattered waves in unbounded exterior domains is a numerical challenge and the development of fast numerical methods ∗Corresponding author Preprint submitted to Computer Methods in Applied Mechanics and EngineeringAugust 18, 2016 is far from being matured. We are interested in boundary integral formulations 5 of the problem to avoid the use of an artificial boundary with approximate transmission conditions [1, 2, 3, 4, 5] and to allow for recasting the problem (under certain assumptions which will be detailed later) as an integral equation on the surface of the scatterer. -
Basic Diffraction Phenomena in Time Domain
Basic diffraction phenomena in time domain Peeter Saari,1 Pamela Bowlan,2,* Heli Valtna-Lukner,1 Madis Lõhmus,1 Peeter Piksarv,1 and Rick Trebino2 1Institute of Physics, University of Tartu, 142 Riia St, Tartu, 51014, Estonia 2School of Physics, Georgia Institute of Technology, 837 State St NW, Atlanta, GA 30332, USA *[email protected] Abstract: Using a recently developed technique (SEA TADPOLE) for easily measuring the complete spatiotemporal electric field of light pulses with micrometer spatial and femtosecond temporal resolution, we directly demonstrate the formation of theo-called boundary diffraction wave and Arago’s spot after an aperture, as well as the superluminal propagation of the spot. Our spatiotemporally resolved measurements beautifully confirm the time-domain treatment of diffraction. Also they prove very useful for modern physical optics, especially in micro- and meso-optics, and also significantly aid in the understanding of diffraction phenomena in general. ©2010 Optical Society of America OCIS codes: (320.5550) Pulses; (320.7100) Ultrafast measurements; (050.1940) Diffraction. References and links 1. G. A. Maggi, “Sulla propagazione libera e perturbata delle onde luminose in mezzo isotropo,” Ann. di Mat IIa,” 16, 21–48 (1888). 2. A. Rubinowicz, “Thomas Young and the theory of diffraction,” Nature 180(4578), 160–162 (1957). 3. g. See, monograph M. Born and E. Wolf, Principles of Optics (Pergamon Press, Oxford, 1987, 6th ed) and references therein. 4. Z. L. Horváth, and Z. Bor, “Diffraction of short pulses with boundary diffraction wave theory,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 63(2), 026601 (2001). 5. P. Bowlan, P. Gabolde, A. -
Chapter 22 Wave Optics
Chapter 22 Wave Optics Chapter Goal: To understand and apply the wave model of light. © 2013 Pearson Education, Inc. Slide 22-2 © 2013 Pearson Education, Inc. Models of Light . The wave model: Under many circumstances, light exhibits the same behavior as sound or water waves. The study of light as a wave is called wave optics. The ray model: The properties of prisms, mirrors, and lenses are best understood in terms of light rays. The ray model is the basis of ray optics. Chapter 23 . The photon model: In the quantum world, light behaves like neither a wave nor a particle. Instead, light consists of photons that have both wave-like and particle-like properties. This is the quantum theory of light. Physics 43 © 2013 Pearson Education, Inc. Slide 22-29 Diffraction depends on SLIT WIDTH: the smaller the width, relative to wavelength, the more bending and diffraction. Ray Optics: Ignores Diffraction and Interference of waves! Diffraction depends on SLIT WIDTH: the smaller the width, relative to wavelength, the more bending and diffraction. Ray Optics assumes that λ<<d , where d is the diameter of the opening. This approximation is good for the study of mirrors, lenses, prisms, etc. Wave Optics assumes that λ~d , where d is the diameter of the opening. d>1mm: This approximation is good for the study of interference. Geometric RAY Optics (Ch 23) nn1sin 1 2 sin 2 ir James Clerk Maxwell 1860s Light is wave. Speed of Light in a vacuum: 1 8 186,000 miles per second c3.0 x 10 m / s 300,000 kilometers per second 0 o 3 x 10^8 m/s Intensity of Light Waves E = Emax cos (kx – ωt) B = Bmax cos (kx – ωt) E ωE max c Bmax k B E B E22 c B I S maxmax max max 2 av 2μ 2 μ c 2 μ o o o I E m ax The Electromagnetic Spectrum Visible Light • Different wavelengths correspond to different colors • The range is from red (λ ~ 7 x 10-7 m) to violet (λ ~4 x 10-7 m) Limits of Vision Electron Waves 11 e 2.4xm 10 Interference of Light Wave Optics Double Slit is VERY IMPORTANT because it is evidence of waves. -
The Double Slit Experiment Re-Explained
IOSR Journal of Applied Physics (IOSR-JAP) e-ISSN: 2278-4861.Volume 8, Issue 4 Ver. III (Jul. - Aug. 2016), PP 86-98 www.iosrjournals.org The Double Slit Experiment Re-Explained Mahmoud E. Yousif Physics Department - The University of Nairobi P.O.Box 30197 Nairobi-Kenya Abstract: The wavelet envisioned by Huygen’s in diffraction phenomenon is re-interpreted as a Polarized Wave (PW) after passing through slit/hole/or biaxial crystals which removed the electric field component from the Electromagnetic Radiation (EM-R), the resulted wave is what is known as the Conical Diffraction (CD) beam, the PW is originated from the Circular Magnetic Field (CMF) produced by accelerated electrons, integrated with the Electric Field (EF) during the Flip-Flop (F-F) mechanism producing EM-R; hence the passing of light through a single hole/slit/biaxial crystals, resulted in a PW which reproduced as rings on the monitor screen in single wave diffraction, while the interference of two such PW in double slits experiment, produced constructive or destructive interference forming patches on the monitor screen; and the perceived electron diffraction is an enter of two CMF from an accelerated electron into two slits then emerged to interfere constructively or destructively, and appears as patches, in addition to the electron which entered and emerged from the slit with the intense CMF, the paper finally derived the origin of Planck’ constant (h) for the second time; the logical interpretation of double slits diffraction will restore the common sense in the physical world, distorted by the pilot wave. Keywords: Double Slit Experiment; wavelet; Circular Magnetic Field; electron diffraction; polarization; origin of Planck’ constant.