Spatio-angular multiplexing geometry for volume holographic storage
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsMuthuveerappan Jeganathan, Matthew C. Bashaw, Lambertus Hesselink
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Abstract
Partially overlapping holograms are stored in a cylindrical volume holographic storage medium capable of rotation about and translation along its longitudinal axis. The reference and signal beams are mutually perpendicular, and each is perpendicular to the longitudinal axis. An index-matched housing encloses the medium laterally. An optional helically-varying optical axis (c-axis) orientation allows recording at constant angular intervals over a full revolution. Signals from stored pages are used to dynamically adjust the positioning of the medium relative to the light beams as the medium continuously spins at high velocity, and to control the access of the signal beam to the readout camera.
Claims13
A holographic data storage system comprising:
- a) a volume holographic storage medium having a longitudinal axis and a c-axis in a plane substantially perpendicular to said longitudinal axis, said c-axis having a helically-varying orientation along said longitudinal axis;
- and
- b) optics for establishing a reference beam and a signal beam incident on said medium for storing multiple data pages therein.
A holographic data storage method in a volume holographic storage medium comprising the steps of:
- a) establishing in said medium a longitudinal axis and a c-axis in a plane substantially perpendicular to said longitudinal axis;
- b) establishing a helically-varying orientation of said c-axis along said longitudinal axis;
- and
- c) storing multiple data pages in said medium by directing a reference beam and a signal beam on said medium.
A holographic data retrieval method from a volume holographic storage medium comprising the steps of:
- a) establishing in said medium a longitudinal axis and a c-axis in a plane substantially perpendicular to said longitudinal axis;
- b) establishing a helically-varying orientation of said c-axis along said longitudinal axis;
- and
- c) retrieving multiple data pages from said medium by directing a reference beam on said medium.
Dependencies are inferred from the claim text.