Holographic storage device with faceted surface structures and associated angle multiplexing method

A holographic storage apparatus comprising:

• a photorecording medium layer which includes a first side and a second side and which encompasses a plurality of volume holographic storage regions;
• a first layer that is disposed on the first side of the photorecording medium layer and that includes a plurality of respective first surface structures with respective first surface structures including respective first and second facets with surfaces facing toward the photorecording medium layer inclined at an angle of 50°-130° or less relative to one another;
• and
• a second layer that is disposed on the second side of the photorecording medium layer and that includes a corresponding plurality of respective second surface structures with respective third and fourth facets with surfaces facing toward the photorecording medium layer inclined at an angle of 50°-130° relative to one another;
• wherein each respective volume holographic storage region is disposed between a respective first surface structure and a respective corresponding second surface structure.

A holographic storage apparatus comprising:

• a photorecording medium layer which includes a first side and a second side and which encompasses a plurality of volume holographic storage regions;
• a first layer that is disposed on the first side of the photorecording medium layer and that includes a plurality of respective first surface structures with respective first surface structures including respective first and second facets with respective inner and outer surfaces, wherein respective inner surfaces facing toward the photorecording medium layer are inclined at an angle of 50°-130° relative to one another;
• and
• a second layer that is disposed on the second side of the photorecording medium layer and that includes a corresponding plurality of respective second surface structures with respective third and fourth facets with respective outer surfaces facing away from the photorecording medium, wherein respective outer surfaces of respective third facets are parallel to respective outer surfaces of corresponding respective first facets;
• wherein each respective volume holographic storage region is disposed between a respective first surface structure and a respective corresponding second surface structure.

A method of recording holograms within a holographic storage apparatus comprising:

• providing a photorecording medium layer which includes a first side and a second side and which encompasses a plurality of volume holographic storage regions respectively disposed between respective first surface structures and respective corresponding second surface structures, each respective first surface structure including respective first and second facets that upstand from the first side of the photorecording medium layer, and each respective corresponding second surface structure including a respective third facet that respectively upstands from the second side of the photorecording medium layer parallel to a respective first facet of a corresponding respective first surface structure;
• and
• shining an object signal beam onto a respective first facet of a respective first surface structure while directing a reference beam shining onto a respective second facet of the respective first surface structure to be incident upon the respective second facet at different ones of a prescribed set of multiple discrete incidence angles during different recording times.
• whereby multiple respective holograms can be recorded in a respective given holographic storage region disposed between the respective first and second surface structures.

A method of reading stored holograms from a holographic storage apparatus comprising:

• providing a photorecording medium layer which includes a first side and a second side and which encompasses a plurality of volume holographic storage regions respectively disposed between respective first surface structures and respective corresponding second surface structures, each respective first surface structure including respective first and second facets that upstand from the first side of the photorecording medium layer, and each respective corresponding second surface structure including a respective third facet that respectively upstands from the second side of the photorecording medium layer parallel to a respective first facet of a corresponding respective first surface structure;
• and
• directing a reference beam shined onto a respective second facet of the respective first surface structure to be incident upon the respective second facet at different ones of a prescribed set of multiple discrete incidence angles during the different image forming times;
• whereby different respective image forming beams produced from multiple respective stored holograms shine out from a respective third facet of the respective second surface structure during the different image forming times.

A method of accessing a holographic storage apparatus comprising:

• providing a photorecording medium layer which includes a first side and a second side and which encompasses a plurality of volume holographic storage regions respectively disposed between respective first surface structures and respective corresponding second surface structures, each respective first surface structure including respective first and second facets that upstand from the first side of the photorecording medium layer, and each respective corresponding second surface structure including a respective third facet that respectively upstands from the second side of the photorecording medium layer parallel to a respective first facet of a corresponding respective first surface structure;
• directing a reference beam shined onto a respective second facet of the respective first surface structure to be incident upon the respective second facet at different ones of the prescribed set of multiple discrete incidence angles during the different image forming times;
• whereby different respective image forming beams produced from multiple respective stored holograms shine out from a respective third facet of the respective second surface structure during the different image forming times;
• and
• subsequently, directing a reference beam shined onto a respective second facet of the respective first surface structure to be incident upon the respective second facet at different ones of the prescribed set of multiple discrete incidence angles during the different image forming times;
• whereby different respective image forming beams produced from multiple respective stored holograms shine out from a respective third facet of the respective second surface structure during the different image forming times.