Roger Rothenberg
holograms

Using the LitiHolo Holography Kit (http://www.litiholo.com/hologram_kits.htm), I created transmission holograms and attempted to create a reflection hologram.

Transmission Hologram Procedure:
In the dark room, I assembled the LitiHolo kit as instructed (see image 1), with the object to be rendered in the delineated box on the black plastic base (with rubber foundation to reduce vibration). I turned on the laser, turned off all other light in the darkroom (save for a blue darkroom LED [the LED’s blue wavelength, while illuminating the room enough for me to get around, did not affect the hologram, which was produced by red light]), and used white paper to ensure that the laser spread to the whole surface of the spot I would place the photosensitive glass. I used a black cardboard “shutter” to block the laser’s path to the object so that I could position the photo glass without exposure. After waiting one minute for the setup to settle (LitiHolo instructions recommend three minutes for a clearer hologram), I removed the shutter. After waiting approximately five minutes (as recommended by LitiHolo), I removed the object and made sure the hologram had been recorded. At this point it was safe to turn the light back on, as the hologram was finished and would not be exposed further. See image 3 for an example transmission hologram.

Reflection Hologram Procedure:
There were no instructions on creating a reflection hologram from the LitiHolo kit, but I attempted to create my own setup (see image 2) based on more detailed procedures for reflection holograms. Other sets of instructions recommended a greater distance between laser and recording glass, so I increased the spacing between the laser mount and object base provided by LitiHolo. I rotated the base so that the slot for the photo glass was between laser and object. From this point, I proceeded as I did with the transmission hologram. After getting some unremarkable results, I tried again, this time with an additional non-photo glass placed behind the object, with the rationale that this might increase the amount of light scattered from the object onto the photo glass. This did produce a more visible reflection hologram.

Though the above procedures did result in visible holograms, several factors might have improved their quality:

• Decreasing ambient vibrations would have made for a sharper, more precise holographic image. While this might be difficult in the school’s darkroom, some kind of shock-absorbing foundation beneath the setup (such as sand) might help
• Further fine-tuning of the laser’s path of illumination would have made for more centered holograms. Many of those I created had blank space below or around the hologram, indicating unused parts of the photo glass
• Additional mirrors may have allowed for a more controlled setup of the direction of the interfering beams. LitiHolo did not provide additional mirrors
• A more powerful laser might have allowed for a decreased exposure time, which in turn would create a shorter window for vibrations to disrupt the image

Image 1: Transmission Hologram Setup

Image 2: Reflection Hologram Setup

Image 3: Example Transmission Hologram of Car Figurine With Hood Open

Our group will be creating holograms using the holography tools in an attempt to gain a better grasp of how they are made and the processes behind their creation. We also plan to explore the various types of holograms that we can create with the tools available to us. While we run across holograms in many different forms and applications in our daily lives, we–and many others, have little to no understanding of the actual technology at work. We anticipate that this will be a very engaging experiment.