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US 5,331,445 AGranted
Increased Bragg angle sensitivity hologram system and method
AssigneeInternational Business Machines Corporation
InventorsLeRoy D. Dickson, Matthias C. Krantz
Life of this patent
Estimating the term…
Abstract
A hologram system comprises two volume holograms on two separate substrates which are cemented together with an optical cement. The two volume holograms are manufactured with identical Bragg planes. The two volume holograms are oriented with respect to one another such that the Bragg planes are optically aligned. The result is that the two volume holograms operate as a single thicker volume hologram wherein the Bragg angle sensitivity is greatly increased.
Claims36
A hologram system comprising:
- a first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L.sub.1 apart;
- a second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L.sub.2 apart, .PHI..sub.2 being equal to .PHI..sub.1 and L.sub.2 being equal to L.sub.1, the second volume hologram oriented with its Bragg planes parallel with the Bragg planes of the first volume holograms;
- and
- a means for optically coupling the first and second volume holograms.
1 more element
A hologram system comprising:
- a first substrate;
- a first volume hologram overlying the first substrate, the first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L.sub.1 apart;
- a second substrate;
- a second volume hologram overlying the second substrate, the second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L.sub.2 apart, .PHI..sub.2 being equal to .PHI..sub.1 and L.sub.2 being equal to L.sub.1, the second volume hologram being oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram;
- and
- an optical cement connecting the first volume hologram to the second volume hologram.
3 more elements
A method for making a hologram system comprising the steps of:
- positioning a first and a second volume hologram in optical communication with one another, the first and second volume holograms both having Bragg planes at the same angle and with the same Bragg plane spacing;
- rotationally moving the first and second volume holograms about a first axis perpendicular to the planar surfaces of the first and second volume holograms relative to one another until their respective Bragg planes are parallel;
- translationally moving the first and second volume holograms along a second axis parallel to the planar surfaces of the first and second volume holograms relative to one another until the desired amount of diffraction efficiency is achieved.
A hologram system comprising:
- an optical data storage medium;
- a radiation source for generating two radiation beams having an angle of divergence;
- a transmission means for transmitting the two radiation beams to the medium;
- a reception means for receiving two reflected radiation beams from the medium;
- and
- a hologram assembly for receiving and separating the two reflected radiation beams comprising a first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L.sub.1 apart, and a second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle .PHI..sub.2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L.sub.2 apart, .PHI..sub.2 being equal to .PHI..sub.1 and L.sub.2 being equal to L.sub.1, the second volume hologram oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram, and means for optically coupling the first and second volume holograms.
3 more elements
Dependencies are inferred from the claim text.