Abstract: The invention is directed to a holographic data storage system including a spatial light modulator device (SLM) that comprises optical elements in the form of polymer dispersed liquid crystal (PDLC) elements. The PDLC elements are individually controllable, and can be made substantially transparent or substantially diffusive. The “on” or “off” state of each PDLC element is defined by whether the given PDLC element is transparent or diffusive. Additional states may also be defined for the PDLC elements, e.g., based on a level of diffusiveness of the PDLC elements. Also, a mirror layer may be added adjacent the PDLC elements to define a reflective-mode SLM. In any case, the SLM is used to encode bit maps into a holographic object beam.

Abstract: The invention is directed to a spatial light modulator device that can improve holographic data recording systems, and various methods and systems incorporating the device. The spatial light modulator device includes a diffusive element to diffuse or scatter a data encoded object beam. For example, the diffusive element may comprise a two-layer diffusive laminate formed, a polymer dispersed liquid crystal material, or another diffusive material. The diffusive element can be formed over the output window, or may comprise the output window of the spatial light modulator device. In any case, the diffusive element can slightly scatter the data encoded object beam, which can significantly reduce undesirable zero-order burning effects in a holographic medium positioned in proximity to a Fourier transform plane.

Abstract: The invention provides a dichroic coating for holographic media. The dichroic coating is substantially non-reflective of light at a first wavelength and substantially reflective of light at a second wavelength. A holographic recording material of the medium can be formulated to be sensitive to the first wavelength of light, but generally insensitive to the second wavelength. A probe beam at the second wavelength can be used to interrogate the medium and identify tracking features.

Abstract: Holographic data storage media having a sandwiched construction are described in which a holographic recording material is sandwiched between two substrates. The holographic media formulation is often formed of two or more components mixed to obtain a homogeneous formulation. The holographic media formulation may include two or more components which are mixed together prior to injection between the substrates. Curing of the holographic media formulation is substantially avoided during mixing, yet accelerated after the formulation is injected between the substrates. Accordingly, the system and techniques can be used to improve the large scale manufacturability of such media by allowing for fabrication of such media within reasonable cycle times, such as less than one minute, while adhering to stringent requirements for optical clarity and parallelism.

Abstract: Mastering techniques are described that can improve the quality of a master used in data storage disk manufacturing. In particular, multi-spot mastering techniques and interferometric mastering techniques are described. The techniques described can reduce track pitch variations between adjacent tracks of the master. Also, the techniques may provide improved consistency in the features created on the master.

Abstract: The invention is directed to holographic recording techniques that generate a data encoded object beam and a reference beam using a spatial light modulator of the holographic recording system. An input light source, e.g., comprising laser light conditioned by optical elements, can be used to illuminate the spatial light modulator. Different portions of the spatial light modulator are used to create the data encoded object beam and the reference beam, which are then made to interfere in a holographic medium to record a hologram.

Abstract: The invention is directed to holographic recording techniques that generate a data encoded object beam and a reference beam using a spatial light modulator of the holographic recording system. An input light source, e.g., comprising laser light conditioned by optical elements, can be used to illuminate the spatial light modulator. Different portions of the spatial light modulator are used to create the data encoded object beam and the reference beam, which are then made to interfere in a holographic medium to record a hologram.

Abstract: In one embodiment, holographic data storage medium includes a first thermoplastic substrate portion having a thickness less than approximately 2 millimeters and a second thermoplastic substrate portion having a thickness less than approximately 2 millimeters. A holographic recording material may be sandwiched between the first and second thermoplastic substrate portions. By making thermoplastic substrate portions sufficiently thin, edge wedge problems can be avoided.