mikel@bmcg.UUCP (Mike Lesher) (12/02/85)
A reflection is produced by a argon or helium-neon laser beam traveling through a lens to spread it out into illuminating light. The light passes through a low speed/high density film and strikes the subject. Some light is reflected by the subject back toward the film. The interference pattern generated by the light from both directions is recorded in the film. The film is then developed and bleached and when the laser, or another light source, is placed in the same position, the film recreates the interference pattern that would have been there as if the subject was still present. All holograms work on interference between two sources of light, one from a reference, and one from the reflections of the subject. I have created standard holograms before but have not tried a reflection hologram because I didn't have the equipment to bleach the film. The equipment I used was from Edmund Scientific, a mail order catalog company. Since a picture is worth a thousand words, here is a diagram of making and viewing a reflection hologram. Creation Viewing laser | | lens Eye Light Eye / \ \ / \ / / \ \/ \/ / \ / \ Film ---------- --------- / \ / \ / subject \ / Subject \ (Recreated) Mike Lesher Burroughs DSG, San Diego, CA. (..!bmcg!mikel)