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Magnetooptic Disk Readout With Fresnel Circularly-Polarizing Prism

IP.com Disclosure Number: IPCOM000037712D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Yao, S: AUTHOR

Abstract

The readout scheme for a magnetooptic disk is proposed in the figure.

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Magnetooptic Disk Readout With Fresnel Circularly-Polarizing Prism

The readout scheme for a magnetooptic disk is proposed in the figure.

The polarization of the laser beam at 1 and 2 is p-polarized. After it is reflected from the active layer of the optic disk, the polarization at 3 is elliptically polarized, i.e.: Ep

+exp(i0)Es

where 0 is the phase difference and it varies from 0 to 360 degrees. The polarization at point 5, after two partially polarizing beam splitter cubes (PPBS1, PPBS2), can become: 1

+exp(i0)

This light is composed of both right and left circularly polarized light, and the percentages of these two components are different. When light enters a Fresnel circularly-polarizing prism, these two components will separate into two beams. Therefore, a differential detection can detect mark and no mark on the disk.

(Image Omitted)

Disclosed anonymously.

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