Making Holograms with Lab Equipment

Making Holograms with

Standard Laboratory Equipment

By T. H. Jeong and Alec Jeong

1. INTRODUCTION

In the article "Simple Holography" we lay out a process that allows you to make holograms not only as simply as possible, but also safely and economically for schools, young people, and hobby enthusiasts. The process require a basic set up using equipment and materials commonly found around your home.

The following memo below is an addendum to "Simple Holography". It provides you insight into making reflection holograms if you have access to standard laboratory equipment available in many schools.

2. SETTING UP THE LAB EQUIPMENT TO MAKE REFLECTION HOLOGRAMS

The photograph below shows you how to make use of standard equipments available in most school laboratories to make reflection holograms. The hardware needed are:

Lab stand
Right-angle clamps
Rod with a clothespin glued to it
Small dish
Computer mouse pad

As shown, the diode laser is held by the clothespin with the laser light directed downward. The object to be recorded (in this case, a figurine inside a small dish) is place on top of a computer mouse pad for vibration isolation. Arrange the laser and the object so that the illumination is as even as possible.

Below is a close up of the small dish. It is a convenient and stable method of making exposures if the laser is mounted on a lab stand with the light directed downwards.

Put some shiny and hard objects with details in a dish that are smaller than the plate. Now you are ready to make holograms.

2. STEPS FOR MAKING HOLOGRAMS

After you've placed the holographic plate over the small dish, let your set up settle for about 10 - 15 seconds. This helps ensure the plate is stable and won't move during the exposure.

With the room light turned off and a "safe light" (such as a night light) on, place cardboard between the laser and the object without touching either (fold the cardboard slightly so that it can stand on the table top alone). The cardboard serves as a shutter, like that found on a camera.

Now place a holographic plate, with the emulsion (sticky) side facing downward, on top of the object as shown below. The holographic plate must be resting on the solid rim of the dish so that there is no possibility of any movement.

Now lift up the cardboard carefully with the laser light is still blocked. Wait a couple seconds and then remove the cardboard quickly without bumping anything, and expose the holographic plate for 6 to 7 seconds. Then block the laser light again with the cardboard.

The hologram can now be developed with the process described in the article "Simple Holography".

For best results, remember to make sure the laser has been warmed up for at least 5 minutes before any holograms are exposed. Also, minimize any disturbance to the laser (do not touch it or even allow moving air to cross it) which may cause the outputs to become unstable.