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Polarization Gated Writing of Photochemical Holes for FM Polarization Detection in Frequency Domain Storage

IP.com Disclosure Number: IPCOM000041989D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Bjorklund, GC: AUTHOR [+2]

Abstract

A frequency domain system has polarization-gated writing of photochemical holes suitable for frequency modulation (FM) detection. A modular polarization-FM spectroscopy configuration illustration of this system is shown in the drawing. A linearly polarized narrow band laser 10 is passed into a polarization phase modulator 12 which polarizes and modulates the laser light to provide two FM sidebands. Electronic means 14 drives the polarization phase modulator 12 simultaneously with a single RF frequency to produce light with FM sidebands in a different state of polarization than the carrier. The polarized light passes into a pockels cell 16. When the pockels cell 16 is activated by an electrical pulse from write input means 18, the cell 16 rotates the polarization of the incident beams by 90Œ.

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Polarization Gated Writing of Photochemical Holes for FM Polarization Detection in Frequency Domain Storage

A frequency domain system has polarization-gated writing of photochemical holes suitable for frequency modulation (FM) detection. A modular polarization- FM spectroscopy configuration illustration of this system is shown in the drawing. A linearly polarized narrow band laser 10 is passed into a polarization phase modulator 12 which polarizes and modulates the laser light to provide two FM sidebands. Electronic means 14 drives the polarization phase modulator 12 simultaneously with a single RF frequency to produce light with FM sidebands in a different state of polarization than the carrier. The polarized light passes into a pockels cell 16. When the pockels cell 16 is activated by an electrical pulse from write input means 18, the cell 16 rotates the polarization of the incident beams by 90OE. The strong carrier wave exiting from the cell 16 interacts with the photosensitive sample 20 and write an anisotropic hole at the frequency of the laser. The presence of an anisotropic hole will cause a differential polarization change, absorption or phase shift to be experienced between the two FM sidebands which correspond to the hole location. Such a differential will produce a heterodyne-amplified beat signal at the photodetector 24 after it has passed through the polarization analyzer 22. If there is no differential, no beat signal will be produced. The analyzing...