Browse Prior Art Database

Low Noise Hologram Copying Process

IP.com Disclosure Number: IPCOM000053161D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Dickson, LD: AUTHOR

Abstract

This article discusses the use of a narrow band, non-laser light source such as a filtered mercury vapor lamp, in copying holograms.

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Low Noise Hologram Copying Process

This article discusses the use of a narrow band, non-laser light source such as a filtered mercury vapor lamp, in copying holograms.

A known process for copying a volume hologram requires that an unexposed film of holographic recording material be placed in close proximity to the hologram to be copied. This process is described in U.S. Patent 3,752,557. According to that patent, a laser is used to illuminate the hologram to be copied. When the laser beam is transmitted through the hologram being copied, it is split into a zero order (undiffracted) beam and a first order (diffracted) beam. The two beams interfere at the previously unexposed copy material to form new interference patterns having the same image-forming capabilities as the interference pattern in the original hologram.

Due to its relatively long coherence length, a laser produces reflections from support surfaces and within the holographic recording material. The holographic recording of these reflections causes spurious light noise when the finished copy is illuminated.

A narrow band, non-laser light source, such as a filtered mercury vapor lamp, has a very short coherence length. The short coherence length should inhibit or eliminate the holographic copying of reflections, thereby reducing the amount of light noise produced when the finished copy is illuminated.

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