System and method for reflective holographic storage with associated multiplexing techniques

A method of recording successive holograms in a recording medium comprising:

• providing a multilayer holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above the polarization shifting layer;
• propagating a reference beam with a first polarization at an incident direction to a first area of the photorecording medium layer, wherein the reference beam is reflected by the reflective substrate and the polarization shifting layer introduces a polarization shift of the incident and reflected reference beam;
• propagating a data encoded object beam with a second polarization at an incident direction to a first area of the photorecording medium layer, wherein the object beam is reflected by the reflective substrate and the polarization shifting layer introduces a polarization shift of the incident and reflected object beam;
• wherein the incident reference beam and reflected object beam interfere to produce a first interference grating and the reflected reference beam and incident object beam interfere to produce a second interference grating;
• and
• recording successive holograms by translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and object beam are propagated to successive areas of the photorecording medium.

A method of reconstructing successive holograms previously recorded in a holographic storage medium by

• providing a multilayer holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above the polarization shifting layer;
• propagating a reference beam and an encoded object beam at a first direction to a first area of the photorecording medium layer, wherein the reference beam and encoded object beam have a same first polarization and interfere to produce a first interference grating;
• reflecting the reference beam and the encoded object beam with the reflective substrate layer to produce a reflected reference beam and reflected encoded object beam incident the photorecording medium at a second direction,
• altering the reference beam polarization and the encoded object beam polarization with the polarization shifting layer so that the reflected reference beam and reflected encoded object beam have a same second polarization, wherein the reflected reference beam and the reflected encoded object beam interfere to produce a second interference grating, and wherein the first polarization and second polarization are different;
• and
• recording successive holograms by translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and object beam are propagated to successive areas of the photorecording medium,
• the method of reconstructing comprising:
• propagating a probe beam at an incident direction to the first area of the holographic storage media along the same propagation path as the record reference beam, wherein the probe beam propagates through the photorecording medium layer and is reflected by the reflective substrate to produce a reconstruction beam;
• wherein the reconstruction beam is directed away from the holographic storage media along the same propagation path as the record object beam to a polarizing beam splitter;
• and
• deflecting the reconstruction beam to a detector.

A method of reconstructing successive holograms previously recorded in a holographic storage medium by

• providing a multilayer holographic storage media comprising a reflective substrate layer, and a photorecording medium layer disposed above the reflective substrate layer;
• propagating a reference beam at a record incident angle with respect to the normal to the holographic storage media and direction through a first imaging lens to a first area of the photorecording medium layer, wherein the reference beam is reflected by the reflective substrate, wherein the focal point of the first lens is at the intersection between the photorecording medium layer and the reflective substrate;
• propagating a data encoded object beam from a spatial light modulator at an incident normal direction to a first area of the photorecording medium layer, wherein the object beam is reflected by the reflective substrate;
• wherein the incident reference beam and incident object beam interfere to produce a first interference grating and the reflected reference beam and reflected object beam interfere to produce a second interference grating;
• and
• recording successive holograms by translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and object beam are propagated to successive areas of the photorecording medium,
• the method of reconstructing comprising:
• propagating a phase conjugate probe beam at a reconstruct incident angle measured with respect to the normal to the holographic storage media and direction through a second lens to the first area of the holographic storage media, wherein the reconstruct incident angle is equal to the record incident angle but on an opposite side of a normal to the holographic storage media, wherein the probe beam is reflected by the reflective substrate to produce a reconstruction beam, wherein the focal point location of the second lens is equal to the focal point location of the first lens;
• wherein the reconstruction beam is directed away from the holographic storage media along the same propagation path as the record object beam through the imaging lens to a polarizing beam splitter;
• and
• deflecting the reconstruction beam to a detector.

A method of reconstructing successive holograms previously recorded in a holographic storage medium by

• providing a multilayer holographic storage media comprising a reflective substrate layer, and a photorecording medium layer disposed above the reflective substrate layer;
• propagating a reference beam at an incident normal direction to the holographic storage media through an imaging lens to a first area of the photorecording medium layer, wherein the reference beam is reflected by the reflective substrate;
• propagating a first data encoded object beam from a spatial light modulator at an first incident angle with respect to the normal to the holographic storage media to a first area of the photorecording medium layer, wherein the first object beam is reflected by the reflective substrate;
• propagating a second data encoded object beam from a spatial light modulator at a second incident angle with respect to the normal to the holographic storage media to the first area of the photorecording medium layer, wherein the second incident angle is equal to the first incident angle but on an opposite side of a normal to the holographic storage media, wherein the second object beam is reflected by the reflective substrate,
• wherein the incident reference beam and first object beam interfere to produce a first interference grating and the reflected reference beam and reflected first object beam interfere to produce a second interference grating, and the incident reference beam and second object beam interfere to produce a third interference grating and the reflected reference beam and reflected second object beam interfere to produce a fourth interference grating;
• and
• recording successive holograms by translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and first and second object beam are propagated to successive areas of the photorecording medium,
• the method of reconstructing comprising:
• propagating a phase conjugate probe beam normal to the holographic storage media and direction through a second lens to the first area of the holographic storage media, wherein the probe beam is reflected by the reflective substrate to produce a first and second reconstruction beam;
• propagating the first reconstruction beam away from the holographic storage media along the same propagation path as the record first object beam to a first polarizing beam splitter and deflecting the reconstruction beam to a first detector;
• propagating the second reconstruction beam away from the holographic storage media along the same propagation path as the record second object beam to a second polarizing beam splitter and deflecting the reconstruction beam to a second detector;
• wherein the first spatial light modulator, second spatial light modulator, first detector, and second detector are on a same side of the holographic storage media.

A method of recording successive holograms in a recording medium comprising:

• providing a multilayer holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above a reflective substrate layer;
• providing a wave plate ring with a hollow interior;
• propagating a reference beam at an incident normal direction through the waveplate ring and through an imaging lens to a first area of the photorecording medium layer, wherein the reference beam is reflected by the reflective substrate;
• propagating a data encoded object beam from a spatial light modulator through the hollow interior of the waveplate ring at an incident normal direction through the imaging lens to the first area of the photorecording medium layer, wherein the object beam is reflected by the reflective substrate;
• propagating the object beam and reference beam in a reflected direction through the photorecording medium layer and transparent substrate in a reflected direction, wherein the incident reference beam and incident object beam interfere to produce a first interference grating and the reflected reference beam and reflected object beam interfere to produce a second interference grating;
• and
• recording successive holograms by translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and object beam are propagated to successive areas of the photorecording medium.

A system for recording and reading out holograms in a recording medium comprising:

• a multilayer reflective holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above a reflective substrate layer,
• a laser light source for providing a reference beam and an object beam;
• a pattern encoder for encoding data on the object beam to produce an encoded object beam, wherein the reference beam and object beam are propagated to the photorecording medium layer during a hologram recording process using associated reference beam and object beam optics;
• a detector for receiving a reconstruction beam during a hologram readout process, wherein the detector, pattern encoder, associated object beam optics, and associated reference beam optics are on the same side of the multilayer reflective holographic storage media;
• and
• a means for translating the multilayer holographic storage media or reference and object beam along a shift multiplex direction, wherein the reference beam and object beam are propagated to successive areas of the photorecording medium during the hologram recording process.

A method of recording a plurality of holograms in a recording medium comprising:

• providing a multilayer holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above the polarization shifting layer;
• propagating a reference beam and an encoded object beam at a first direction to a select area of the photorecording medium layer, wherein the reference beam and encoded object beam have a same first polarization and interfere to produce a first interference grating;
• reflecting the reference beam and the encoded object beam with the reflective substrate layer to produce a reflected reference beam and reflected encoded object beam incident the photorecording medium at a second direction,
• altering the reference beam polarization and the encoded object beam polarization with the polarization shifting layer so that the reflected reference beam and reflected encoded object beam have a same second polarization, wherein the reflected reference beam and the reflected encoded object beam interfere to produce a second interference grating, and wherein the first polarization and second polarization are different;
• and
• recording subsequent holograms at the select area by varying the incident angle of the reference beam to the select area of the photorecording medium layer.

A method of recording a plurality of holograms in a recording medium comprising:

• providing a multilayer holographic storage media comprising a photorecording medium layer disposed above a reflective substrate layer;
• propagating a reference beam with a first polarization at an incident direction and incident angle to a select area of the photorecording medium layer, wherein the reference beam is reflected by the reflective substrate;
• propagating a data encoded object beam with a second polarization at an incident direction to a select area of the photorecording medium layer, wherein the object beam is reflected by the reflective substrate;
• wherein the incident reference beam and reflected object beam interfere to produce a first interference grating and the reflected reference beam and incident object beam interfere to produce a second interference grating;
• and
• recording subsequent holograms at the select area by varying the incident angle of the reference beam to the select area of the photorecording medium layer.

A system for recording and reading out holograms in a recording medium comprising:

• a multilayer reflective holographic storage media comprising a reflective substrate layer, a polarization shifting layer disposed above the reflective substrate layer, and a photorecording medium layer disposed above the polarization shifting layer;
• a laser light source for providing a reference beam and an object beam;
• a rotatable beam deflector for varying the angle of incidence of the reference beam on the photorecording medium layer;
• a pattern encoder for encoding data on the object beam to produce an encoded object beam, wherein the reference beam and object beam are propagated to the photorecording medium layer during a hologram recording process using associated reference beam and object beam optics;
• and
• a detector for receiving a reconstruction beam during a hologram readout process, wherein the detector, pattern encoder, associated object beam optics, and associated reference beam optics are on the same side of the multilayer reflective holographic storage media.