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Ferroelectric Beam Addressable File Utilizing Thermoelectric Writing and Electro Optic Readout

IP.com Disclosure Number: IPCOM000077461D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Jacobs, JT: AUTHOR [+2]

Abstract

The device consists of a ferroelectric material on a disk, tape, or chip with external electrode layers. Laser sources are utilized for thermally writing information on the material in the presence of the electrical biasing field. Associated optics and photodetectors are used to electro-optically read the information, as with known beam-addressable file systems. The unstructured storage plane leads to low-material costs.

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Ferroelectric Beam Addressable File Utilizing Thermoelectric Writing and Electro Optic Readout

The device consists of a ferroelectric material on a disk, tape, or chip with external electrode layers. Laser sources are utilized for thermally writing information on the material in the presence of the electrical biasing field. Associated optics and photodetectors are used to electro-optically read the information, as with known beam-addressable file systems. The unstructured storage plane leads to low-material costs.

Information is stored by polarizing the ferroelectric material in one of two polarization directions. This is achieved by local laser heating of a spot, until the coercive field becomes less than the applied electrical biasing field. By adjusting the value of the applied field only the region that is locally heated will be switched.

Nondestructive readout (NDRO) is achieved by using one of several optical techniques for determining the sense of local polarization. For example, some ferroelectric materials are sufficiently birefringent, that the local polarization can be detected by monitoring the phase shift of the polarized light that is transmitted or reflected from the ferroelectric. This is analogous to monitoring the Faraday rotation in the analogous magneto-optic device.

Another method of sensing the information involves monitoring the intensity of the reflected or transmitted light. In this mode of operation, the light is modulated by the orienta...