Browse Prior Art Database

Optical Readout Using Europium Fluoride

IP.com Disclosure Number: IPCOM000095375D
Original Publication Date: 1965-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Shafer, MW: AUTHOR [+3]

Abstract

To be useful a magneto-optical memory device must impart to a polarized reading beam an amount of rotation large enough to be readily detected by ordinary analyzing devices without adversely affecting the resolution and intensity of the beam. This device fulfills these requirements by employing europium fluoride as a Faraday rotational medium to provide enhanced optical readout properties.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 74% of the total text.

Page 1 of 2

Optical Readout Using Europium Fluoride

To be useful a magneto-optical memory device must impart to a polarized reading beam an amount of rotation large enough to be readily detected by ordinary analyzing devices without adversely affecting the resolution and intensity of the beam. This device fulfills these requirements by employing europium fluoride as a Faraday rotational medium to provide enhanced optical readout properties.

In this device, the polarized reading beam passes through a layer of europium fluoride. The beam then is reflected from the magnetic memory medium, a superconducting sheet film for example and again passes through the europium fluoride layer to an analyzer. The incidence angle of the light beam is greatly exaggerated in the drawing the beam actually being nearly normal to the incident surface. Each active bit-storage spot in the memory medium has a magnetic field which is directed normal to the surface of this medium. The effect of this field upon the europium fluoride in the neighborhood of the active spot is such as to provide a greatly enhanced rotation of the beam's polarization plane. The device is particularly well-adapted to operate in the cryogenic temperature range below 100 degrees K. Here europium fluoride has its greatest rotational property.

The extraordinarily high concentration of divalent europium ions in europium fluoride is responsible for its unusual rotational property. This enables the europium fluoride to be utilized...