April 10^TH, 2001

By Jeff Whittaker - www.PhysicsLessons.com

Mark Davids, Physics Teacher and former MDSTA President welcomes teachers to the Holography Workshop.

Mark Davids pulled together a wonderful workshop. On April 10th, functioning as ringmaster, he welcomed teachers from the states of Michigan and Ohio to his well-equipped classroom, which is in Grosse Point, Michigan. He then introduced University of Michigan Professor Emmett Leith as one of the important "fathers" of holography.

Professor Leith spoke with authority and style on the development of holography over the past 35 years. He also described the different scientific methods by which holograms are constructed and their application to industrial use.

After a brief break groups of teachers started making holograms. While waiting to get into the darkroom, Professor Leith displayed some truly amazing holograms, one of which was an alarmingly life-like, life-sized and three dimensional image of a bearded man.

If you have ever created photographic prints you could recognize the similarity to creating a hologram. The main differences were: 1. the light source used was a diode laser with red light, and 2. the photographic paper was substituted with an emulsion-coated glass plate.
The following are the procedure steps needed to create this type of hologram:

1.  Set up the system on the Holography Table (see below).
2.  Use a holography safelight to provide minimal visibility after dark adaptation.
3.  After warming up for a few minutes, the laser will produce light with a constant wavelength.
4.  With the elliptical beam in a horizontal orientation, arrange the system so that the object is illuminated as evenly as possible.
5.  Block the beam near the laser with a "shutter," such as an index card, to prevent light from reaching the object.
6.  Place a holographic plate in contact with the object (on the same side as the laser), with the emulsion (sticky) side facing it. Make sure the film will not move during exposure.
7.  After a settling time of a few seconds, make an exposure of 5 seconds by lifting and lowering the "shutter."
8.  Develop the film according to the instructions in the chemical kit. After development, the dried hologram can be viewed with a pen flashlight or any incandescent point source.

The hologram of a large nickel that I created turned out great, and when I showed it to my students the next day, several mistook it for a real image of a nickel that they imagined was hidden from view. According to Mark, all 34 teachers were succesful in making holograms. Thanks Mark!

This workshop was sponsored by the MDSTA and Arbor Scientific. For more information on how to make holograms in your classroom, visit the links below.

midwest-laser.com

Laser Diode Modules

Arbor Scientific Holography Kits

Emmett Leith, University of Michigan Professor, who is one of the founders of holography, gave an engaging history and theory lecture.

Some of the equipment needed to create holograms