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Opticl Sweep and Recording System

IP.com Disclosure Number: IPCOM000092749D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

McDonnell, JA: AUTHOR

Abstract

The system in drawings A and B utilizes a modulated, polarized laser beam for writing on and reading from photographic films. The memory utilizes laser element 7, resident between mirror 9 and KDP mirror 8. The end portions of element 7 are tapered to a Brewster angle to provide a polarized beam 7a. The latter is activated when a voltage is impressed upon mirror 8. This varying voltage, representing data input, is applied to data input terminal 25 forming a part of switch 30. Polarized beam 7a passes through modulator 3. The latter comprises right circular polarizing crystal 13, left circular polarizing crystal 14 and ZnS crystal 12 situated between them. Crystals 13 and 14 each have birefringent characteristics causing beam 7a to have a circular polarized component.

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Opticl Sweep and Recording System

The system in drawings A and B utilizes a modulated, polarized laser beam for writing on and reading from photographic films. The memory utilizes laser element 7, resident between mirror 9 and KDP mirror 8. The end portions of element 7 are tapered to a Brewster angle to provide a polarized beam 7a. The latter is activated when a voltage is impressed upon mirror 8. This varying voltage, representing data input, is applied to data input terminal 25 forming a part of switch 30. Polarized beam 7a passes through modulator 3. The latter comprises right circular polarizing crystal 13, left circular polarizing crystal 14 and ZnS crystal 12 situated between them. Crystals 13 and 14 each have birefringent characteristics causing beam 7a to have a circular polarized component. Such is clockwise or counterclockwise depending upon the orientation of crystals 13 and 14.

The light component emanating from crystal 13 is modulated by the rotating field of crystal 12. The field is generated in accordance with the variations in the voltage applied to lines 10 and 11 connected to crystal 12. Because of the orientation of crystal 14 which is opposite to the orientation of crystal 13, the modulated component beam emanating from crystal 14 is selected. The basic frequency of the beam is blocked out. The effect of this is to cause a shift in the frequency of the laser beam.

On leaving crystal 14, the modulated beam passes through multiple prism 15. The latter causes refraction of the beam in the direction 24 as it impinges on film 5 during write operations while data input in the form of a varying voltage i...