Apparatus for reading from and/or writing to holographic storage media
AssigneeThomson Licensing
InventorWolfgang Hossfeld
Life of this patent
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Abstract
An apparatus for reading a data page from and/or writing a data page to a holographic storage medium includes a common aperture arrangement of one or more reference beams and an object beam or a reconstructed object beam. One or more spatial light modulators are provided for generating the one or more reference beams by modulating a light beam with a modulation pattern having a spatial frequency higher than the spatial frequency of the data page.
Claims13
An apparatus for writing a data page with a data pattern to a holographic storage medium, with a common aperture arrangement of an object beam and one or more reference beams, wherein the apparatus comprises:
- a light source for generating a light beam;
- one or more spatial light modulators for imprinting a pattern onto the light beam to generate the object beam and the one or more reference beams, wherein said pattern is a superposition of the data pattern of the page and a modulation pattern having a spatial frequency higher than a spatial frequency of the data pattern;
- and
- a pair of Fourier lenses and a spatial filter arranged in a common focal plane of the pair of Fourier lenses for filtering the object beam and the one or more reference beams;
- and
- a Fourier objective lens for illuminating the one or more reference beams and the object beam carrying the data page into the holographic storage medium, wherein the same portion of the Fourier objective lens is used for illuminating the one or more reference beams and the object beam into the holographic storage medium.
A method for writing a data page with a data pattern to a holographic storage medium, with a common aperture arrangement of an object beam and one or more reference beams, the method comprising the steps of:
- generating a light beam;
- imprinting a pattern onto the light beam for generating an object beam;
- and the one or more reference beams, wherein the pattern is a superposition of the data pattern of the page and a modulation pattern having a spatial frequency higher than a spatial frequency of the data pattern;
- filtering the object beam and the one or more reference beams with a pair of Fourier lenses and a spatial filter arranged in a common focal plane of the pair of Fourier lenses;
- and
- illuminating the one or more reference beams and the object beam into the holographic storage medium with a Fourier objective lens, wherein the same portion of the Fourier objective lens is used for illuminating the one or more reference beams and the object beam into the holographic storage medium.
A method for reading a data page with a data pattern from a holographic storage medium, with a common aperture arrangement of an object beam and one or more reference beams, the method comprising the steps of:
- generating a light beam;
- generating one or more reference beams by modulating an inner area of the light beam, the inner area comprising an optical axis of the light beam, with a modulation pattern having a spatial frequency higher than a spatial frequency of the data pattern of the data page;
- filtering the object beam and the one or more reference beams with a pair of Fourier lenses and a spatial filter arranged in a common focal plane of the pair of Fourier lenses;
- and
- illuminating the one or more reference beams into the holographic storage medium with a Fourier objective lens for generating a reconstructed object beam carrying the data page;
- collimating the reconstructed object beam and portions of the one or more reference beams travelling along the reconstructed object beam with a collimating lens, wherein the same portion of the collimating lens is used for collimating the reconstructed object beam and the portions of the one or more reference beams travelling along the reconstructed object beam;
- and
- retrieving the data page from the reconstructed object beam with a detector.
An apparatus for reading a data page with a data pattern from a holographic storage medium, with a common aperture arrangement of an object beam and one or more reference beams, wherein the apparatus comprises:
- a light source for generating a light beam;
- a spatial light modulator for generating one or more reference beams by modulating an inner area of the light beam, the inner area comprising an optical axis of the light beam, with a modulation pattern having a spatial frequency higher than a spatial frequency of the data pattern of the data page;
- a pair of Fourier lenses and a spatial filter arranged in a common focal plane of the pair of Fourier lenses for filtering the object beam and the one or more reference beams;
- a Fourier objective lens for illuminating the one or more reference beams into the holographic storage medium for generating a reconstructed object beam carrying the data page;
- a collimating lens for collimating the reconstructed object beam and portions of the one or more reference beams travelling along the reconstructed object beam, wherein the same portion of the collimating lens is used for collimating the reconstructed object beam and the portions of the one or more reference beams travelling along the reconstructed object beam;
- and
- a detector for retrieving the data page from the reconstructed object beam.
Dependencies are inferred from the claim text.