6C20.10 - Poisson's Spot

See paragraph one in the procedure section.
Code Number:
Demo Title:
Poisson's Spot
Diffraction Patterns & Fresnel Diffraction, Edge Diffraction
Area of Study:
Permanent Poisson's spot optics rail set up. Or, Tptics Table, Laser (2 to 5 mw.), Beam Expander, Small Paper Screen and Holder, Ball Bearings mounted on Glass, Razor Blade, Video Camera.

The expandable beam laser pointer, round headed pins, screen, and video camera are permanently mounted on an optics rail.  Viewing the diffraction patterns around the object with the video camera can be done by focusing the camera onto the back side of the screen.  Adjustment of the 2 axis stage may be needed to get the most intense central spot.  In some cases it will work much better if instead of using the small screen and the video camera, you dispense with these and direct the diffraction pattern onto the screen at the other end of the lecture room.

  • Matthew Hoover, Michael Everhart, Jose D'Arruda, "Poisson Spot with Magnetic Levitation", TPT, Vol. 48, # 2, Feb. 2010, p. 135.
  • Michael E. Harrison, C. Thomas Marek, and James D. White, "Rediscovering Poisson's Spot", TPT, Vol.  35, # 1, p. 18-19, Jan. 1997.
  • Jack Higbie, "More on Poisson's Spot", TPT, Vol. 35, # 4, Apr. 1997, p. 197.
  • Ronald D. Wong, "Still More on Poisson's Spot", TPT, Vol. 35, # 4, Apr. 1997, p. 197.
  • Gordon R. Gore, "Diffraction Photographs with a Laser Pointer", TPT, Vol. 32, # 3, March 1994, p. 174.
  • Robert A. Barttett, "Poisson's Circles?", TPT, Vol. 32, # 6, Sept. 1994, p. 326.
  • Andrew DePino Jr.  "Unusual Diffraction Patterns",  TPT, Vol. 25, # 4, p. 219, April 1987.
  • Timothy Kersey, "The Poisson Bright Spot", TPT, Vol. 23, # 4, April 1985, back cover.
  • John B. Johnston, "Projecting Poisson's Spot", TPT, Vol. 16, # 3, Mar. 1978, p. 179.
  • R. C. Nicklin and J. Dinkins, "Laser Diffraction Photography", TPT, Vol. 12, # 5, May 1974, p. 295.
  • John Dowling, Jr., and John Swanson, "A Short Note on "The Poisson Distribution" Lab", TPT, Vol. 11, # 9, Dec. 1973, p. 543.
  • Mimi S. Lafleur and Peter F. Hinrichsen, "An Experimental Approach to Teaching Statistics", TPT, Vol. 10, # 6, Sept. 1972, p. 314.
  • James Moore, "Viewing Diffraction Fringes", TPT, Vol. 9, # 3, March 1971, p. 153.
  • Michel Gondran, Alexandre Gondran, "Energy Flow Lines and the Spot of Poisson-Arago", AJP, Vol. 77, # 6, June 2010, p. 598.
  • W.R. Kelly, E.L. Shirley, A.L. Migdall, S.V. Polyakov, K. Hendrix, "First- and Second-Order Poisson Spots", AJP, Vol. 77, # 8, August 2009, p. 713.
  • Andrzej Kolodziejczyk, Zbigniew Jaroszewicz, Rodrigo Henao and Orlando Quintero, "An Experimental Apparatus for White Light Imaging by Means of a Spherical Obstacle", AJP, Vol. 70, # 2, Feb. 2002, p. 169.
  • P. M. Rinard, "Large-Scale Diffraction Patterns From Circular Objects", AJP, Vol. 44, # 1, Jan. 1976.
  • O-530:  "Needle, Slit, and Razor Blade",  DICK and RAE Physics Demo Notebook.
  • O-555:  "Poisson's Spot",  DICK and RAE Physics Demo Notebook.
  • O-7f:  Wallace A. Hilton, Physics Demonstration Experiments.
  • L-78:  Richard Manliffe Sutton, Demonstration Experiments in Physics.
  • Jearl Walker,  "A Ball Bearing Aids in the Study of Light and Also Serves As a Lens",  The Amateur Scientist,  November, 1984.
  • Robert Ehrlich, "11.4, Poisson's Bright Spot", Why Toast Lands Jelly-Side Down, p. 176.
  • T. Kallard, "The Poisson - Arago Spot", Exploring Laser Light, p. 184.
  • T. Kallard, "Simple Optical System for Fraunhofer Diffraction Experiments", Exploring Laser Light, p. 188.
  • Wallace A. Hilton, "Arago White Spot", Apparatus Notes, July 1965-December 1972, p. 61.
  • Borislaw Bilash II, David Maiullo, "Poisson Spot- The Inner Light", A Demo a Day: A Year of Physics Demonstrations, p. 351.
  • Jearl Walker, "6.151, Using a Solid Metal Ball to Focus Light", The Flying Circus of Physics Ed. 2, p. 303.
  • Yaakov Kraftmakher, "7.22, Poisson Spot", Experiments and Demonstrations in Physics, ISBN 981-256-602-3, p. 497.
  • Richard E. Berg, "DEMO HINTS: Laser Diffraction", PIRA Newsletter, Vol. 3, # 11, March 31, 1989, p. 3.
  • 5.98, Jearl Walker, "Poisson Spot", The Flying Circus of Physics with Answers.
  • C. Harvey Palmer, "Experiment B13: Demonstration of Fresnel Diffraction by Circular Apertures and Obstructions",  Optics - Experiments and Demonstrations, John Hopkins Press, 1962.
  • "Diffraction Grating, Simple", Selective Experiments in Physics, CENCO, 1962.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.