6D20.32 - CD or DVD Gratings

Code Number:
Demo Title:
CD or DVD Gratings
Diffraction and Dispersion
Area of Study:
Optics, Astronomy
CD or DVD and Laser or Laser Pointer.

Shine the laser pointer on the CD at a very shallow angle, letting the reflection fall on the chalk board or onto a screen.  You should see at least 3 dots, which correspond to the 0th, 1st, and 2nd orders.

The etched CD without the metal coating can be used for some transmission diffraction grating type demo's.

  • Santiago Velasco and Alejandro del Mazo, "Visualization of Four Optics Phenomena in a Single Experiment", TPT, Vol. 57, #6, Sept. 2019, p. 430.
  • Alan J. DeWeerd, "CD, DVD, and Blu-Ray Disc Diffraction with a Laser Ray Box", TPT, Vol. 54, #5, May 2016, p. 300.
  • Athanasios Velentzas, "Teaching Diffraction of Light and Electrons: Classroom Analogies to Classic Experiments", TPT, Vol. 52, #8, Nov. 2014, p. 493.
  • P. J. Ouseph, "CD Rainbows", TPT, Vol. 45, #1, Jan. 2007, p. 11.
  • James L. Hunt, "Five Quantitative Physics Experiments (Almost) Without Special Apparatus", TPT, Vol. 43, #7, Oct. 2005, p. 412.
  • Paul Gluck, "Compact Disk Optics", TPT, Vol. 40, #8, Nov. 2002, p. 468.
  • Tim Knauer, "A Compact Disk Transmission Spectroscope", TPT, Vol. 40, #8, Nov. 2002, p. 466.
  • "Cover Photo", TPT, Vol. 40, #8, Nov. 2002.
  • Scott R. Welty, "Long-Playing Diffraction Grating", TPT, Vol. 19, #3, Mar. 1981, p. 187, also A Potpourri of Physics Teaching Ideas - Optics and Waves, p. 231.
  • Rajeev Khare, "Use of a CD as a Dispersive Element in a Turntable Dye Laser", AJP, Vol. 73, #6, June 2005, p. 559.
  • James E. Kettler, "The Compact Disk as a Diffraction Grating", AJP, Vol. 59, #4, Apr. 1991, p. 367.
  • Wallace A. Hilton, "I-12", Experiments in Optical Physics, p. 39.
  • Martin C. Sagendorf, "Simple Spectroscope Using a Box and a CD", Physics Demonstration Apparatus, 2009. p. 88.
  • Bill Franklin, "The Compact Disc as a Diffraction Grating, Using a Laser", Teaching about Color & Color Vision, 1996, p. 3C-1.
  • Pat Murphy, Ellen Macaulay, and the Staff of the Exploratorium, "Reflections of a CD", Exploratopia, p. 313.
  • Jearl Walker, "6.108, Colors on Finely Grooved Items", The Flying Circus of Physics Ed. 2, p. 286.
  • Roman Ya. Kerzerashvili, "Abstract: Advanced Optics with Laser Pointer and Metersticks", 2005 Apparatus Competition, Salt Lake City, UT.
  • P. J. Ouseph, "Abstract: CD Rainbows", 2005 Apparatus Competition, Salt Lake City, UT.
  • "The Diffraction Grating", Selective Experiments in Physics, CENCO, 1962.
  • "Diffraction Grating, Simple", Selective Experiments in Physics, CENCO, 1959.
  • Curt Suplee, "Lasers and Compact Disks", Everyday Science Explained, National Geographic, p. 120 - 121.

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.