Browse Prior Art Database

Optical Media, Process and System for Storage

IP.com Disclosure Number: IPCOM000110021D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 29K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR

Abstract

Optically active materials are prepared by physical vapor depositing refractory oxides onto substrates at oblique angles (*). These materials exhibit strong optical rotation in cross-polarizers, i.e., complete extinction or transmission can be seen with the sample between two cross-polarizers. The optical activity in these normally isotropic materials is produced by a growth-induced directional void structure. This invention utilizes the birefringency of this class of materials to produce a write only memory with high signal to noise. The object is to alter the material property by local heating. The heated region will cause a change in the void structure (i.e., tending to collapse this region).

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Optical Media, Process and System for Storage

       Optically active materials are prepared by physical vapor
depositing refractory oxides onto substrates at oblique angles (*).
These materials exhibit strong optical rotation in cross-polarizers,
i.e., complete extinction or transmission can be seen  with the
sample between two cross-polarizers.  The optical activity in these
normally isotropic materials is produced by a growth-induced
directional void structure.  This invention utilizes the
birefringency of this class of materials to produce a write only
memory with high signal to noise.  The object is to alter the
material property by local heating.  The heated region will cause a
change in the void structure (i.e., tending to collapse this region).
Therefore, when viewed in cross-polarizers the heated regions will
become less optically active or totally inactive, providing strong
contrast with the untreated surfaces.  With suitable arrangements for
heating (i.e., laser), guidance and motion, reading and interpreting,
this material can act as a permanent storage medium with long term
durability.

      Reference
(*)  T. Mothiro and Y. Taga, "Thin Film Retardation Plate by Oblique
Deposition," Applied Optics 28, 13 (1989).