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Recording and Erasing Apparatus for Thermoplastic Holograms

IP.com Disclosure Number: IPCOM000089882D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Tao, TY: AUTHOR

Abstract

Recording and erasing of a localized hologram are accomplished on a thermoplastic medium overcoating a photoconductor substrate. The same source of radiation is used for both operations. Special types of thermoplastic films and localized heating arrangements are not required.

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Recording and Erasing Apparatus for Thermoplastic Holograms

Recording and erasing of a localized hologram are accomplished on a thermoplastic medium overcoating a photoconductor substrate. The same source of radiation is used for both operations.

Special types of thermoplastic films and localized heating arrangements are not required.

High output power YAG laser 1 provides a laser beam 15 at a wavelength
1.06 mu. Second harmonic generator 2 changes the wavelength of beam 15 to 5300 angstroms. Modified beam 16 is split at beam splitter 5 into beams 17 and
18. For recording information, beam 17 is directed by light deflector 4 to a localized area of storage medium 3. The latter is a thermoplastic film overcoating the photoconductor substrate.

Beam 18 passes through shutter device 7 and information modulating mask 8 to entirely flood medium 3. Beam 17 acts as a reference beam and beam 18 as the information carrying beam. Electro-optic switch 6 is positioned in the path of the output beam from deflector 4 to assure that the polarization direction of beam 17 is the same as the polarization direction of beam 18.

Shutter 7 can take the form of a mechanical disk having spacings of predetermined width. The openings correspond to the time required to record and the opaque portions to the time required to erase the hologram. To enhance the speed of operation of the system, a combination of a polarizer and an electro- optic switch can be used in place of a mechanical disk. R...