Demonstrations

Interference - Laser and Cornell Plate (Db. Slit)

Code Number :	6D10.10
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved..
Condition :	Good
Principle :	Diffraction of Waves
Area of Study :	Optics, Astronomy
Equipment :	Helium-neon laser (2 to 5 mw.), Optics bench, Cornell Plate, Razor Blade, 7 cm Lens.
Procedure :	The slit plate has single, double, and multiple as well as variable slits on it . With the laser as shown you can show a variety of diffraction and interference patterns. Information on the plate is in the file. Two variations of the laser and slit plate demo are as follows. To easily see what the difference between a single and double slit diffraction pattern look like, shine the laser through the double slit pattern. Then with a razor blade cover one of the slits. In this way you can instantly see the difference between the two patterns. Direct a diffuse laser beam onto the central diffraction pattern. Using the 7 cm. lens you can focus two different images. At the focal length you get a row of diffracted dots as if the laser beam was not expanded. Outside the focal length you get an image of the diffraction pattern that is on the slit plate. By using the pointer or the variable slit to block one or more of the diffraction nodes out of the transmitted image, the image will at times become more focused and at other times less focused depending on which nodes are blocked.

References

Ronald Newburgh, "Optical Path, Phase, and Interference," TPT, Vol. 43, # 8, p. 496, Nov. 2005.

"Correction," TPT, Vol. 41, # 2, p. 69, Feb. 2003.

Andrew DePino Jr. "Diffraction Patterns Using a Constant-Velocity Cart." TPT, Vol. 40, # 7, p. 418, Oct. 2002.

Michael I. Sobel, "Algebraic Treatment of Two-Slit Interference," TPT, Vol. 40, # 7, p. 402, Oct. 2002.

Thomas B. Greenslade, Jr., "Quick Measurement of Wavelength of Laser Light," TPT, Vol. 35, # 5, p. 309, May 1997.

Kenneth Ford, "Double-Slit Experiment on Web", TPT, Vol. 35, # 8, Nov. 1997, p. 474.

Rand S. Worland and Matthew J. Moelter, "Hands-On Phasors and Multiple-Slit Interference," TPT, Vol. 35, # 8, p. 486 - 488, Nov. 1997.

William Moebs and Jeff Sanny, "A Simple Description of Coherence", TPT, Vol. 32, # 1, Jan. 1994, p. 54.

Walter Scheider, "Bringing One of the Great Moments of Science to the Classroom," TPT, Vol. 24, # 4, p. 217, April 1986.

Y. P. Hwu, Jeffrey C. Repass, "Young's Experiment Gratings Made Holographically", TPT, Vol. 19, # 4, Apr. 1981, p. 249.

P. F. Hinrichsen, "A Simple Interference Scanner", AJP, Vol. 69, # 8, Aug. 2001, p. 917.

R. D. Bahuguna et al., "Young's Double-Slit Experiment Using Speckle Photography," AJP, p. 531, Vol. 56, # 6, June 1988.

Ol-9: Freier and Anderson, A Demonstration Handbook for Physics.

O-405: "Double Slit with Laser," DICK and RAE Physics Demo Notebook.

Gordon McComb, "Experiments with Double Slits," Lasers, Ray Guns, & Light Cannons, p. 121 -123.

Seville Chapman and Harold Meese, "Effective and Inexpensive Slits for Teaching Physical Optics," Cornell Aeronautical Laboratory, Inc., Buffalo, New York, August 8, 1956.

C. Harvey Palmer, "Experiment B1: Young's Interference," Optics - Experiments and Demonstrations, John Hopkins Press, 1962.

C. Harvey Palmer, "Experiment B19: Demonstration of Missing Orders," Optics - Experiments and Demonstrations, John Hopkins Press, 1962.

"22, Young's Experiment on Interference", Experiments in Optics, Part 1, J. Klinger Scientific Apparatus Corp., Bulletin 101.

T. D. Rossing, C. J. Chiaverina, "5.2, Light Passing Through Two Slits: Young's Experiment", Light Science, Physics and Visual Arts, p. 106.

T. D. Rossing, C. J. Chiaverina, "# 3, Two-Slit Interference", Light Science, Physics and Visual Arts, p. 125.

Robert P. Crease, "Light A Wave: Young's Lucid Analogy", The Prism & The Pendulum, Ch. 5, p. 104 - 117.

"Double Slit Interference", Selective Experiments in Physics, CENCO, 1962.

Mail Questions and Comments to: Dale Stille