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:
In one embodiment, a holographic data storage medium includes a substrate, a holographic recording material, and an optically detectable tracking pattern on the medium. The substrate may have first and second substrate portions. The holographic recording material may be a photopolymer, and the medium may have a sandwiched construction, where the holographic recording material is sandwiched between the first and second substrate portions. The optically detectable tracking pattern may be replicated on at least one of the substrate portions. Alternatively, the optically detectable tracking pattern may be recorded as a holographic grating in the holographic recording material. The tracking pattern may facilitate the ability to pinpoint the location of the holographic bit maps on the holographic medium to within a fraction of a micron.
Abstract:
A data storage master disk and method of making a data storage master disk. The data storage disk master is for use in a data storage disk replication process. The data storage disk molding processes produces replica disks having a surface relief pattern with replica lands and replica grooves. The method includes providing a master substrate. The master substrate is at least partially covered with a layer of photosensitive material. A surface relief pattern having master lands and master grooves is recorded in the data storage disk master, including the steps of exposing and developing the photosensitive material. The exposing and developing of a specified thickness of photosensitive material is controlled to form master grooves extending down to a substrate interface between the master substrate and the layer of photosensitive material, such that the width of the master grooves at the substrate interface corresponds to a desired width of the replica lands.
Abstract:
Holographic data storage media having a sandwiched construction are described in which a holographic recording material is sandwiched between two substrates. The substrates may be formed with fluid containment features in proximity to outer edges of the respective substrates. Also, the substrates may be formed with centerpieces that are recessed relative to the outer surfaces of the respective substrates. Such substrate features can improve and simplify the media fabrication process and may improve media quality.
Abstract:
A system and method for conditioning a photoconductive radiation detector achieve charge redistribution within a photoconductive layer without the need for charge removal or charge injection techniques. A first conditioning voltage is applied across the detector to establish a first electric field. The first electric field is reversed relative to fields applied to the detector during image exposure and image read-out operations. While the first conditioning voltage is maintained, the photoconductive layer is exposed for a period of time to first conditioning radiation having one or more wavelengths selected to penetrate at least a portion of the photoconductive layer. A second conditioning voltage, less than the first conditioning voltage, then can be optionally applied across the detector to establish a forward bias electric field. While the second conditioning voltage is maintained, the photoconductive layer is exposed for a period of time to second, broad spectrum conditioning radiation. The detector can then be placed in a dark environment for a period of time, in a shorted condition, to dark-adapt the photoconductive layer.
Abstract:
The disclosure is directed to optical disks with a microstructured surface formed on a surface of the optical disk. The microstructured surface may be created to promote the adhesion and prevent the migration of a print material applied to the surface of the optical disk. The microstructured surface may be in the form of a plurality of wells or a plurality of discontinuous raised features in the surface. By forming a microstructured surface on the surface of the disk, the optical disk may not need an additional coating to receive the print material while also retaining the print material at a precise location on the surface. In addition, a plurality of standoff features may be formed in an outer surface of the optical disk to help prevent damage to the surface of the optical disk.
Abstract:
A system for precisely determining a position with resolution on the order of nanometers or sub-nanometers is described. In particular, a system is described that utilizes a first and a second sensor assembly to determine a position of a movable element over a distance many times the capable range of operation of either of the individual sensor assemblies. The two sensor assemblies leap-frog one another in an incremental fashion to ensure that at least one of the sensor assemblies is always within it operational range. Positional signals generated by one of the sensor assemblies can be used to calibrate the other sensor assembly, following an adjustment of the other sensor assembly. The described invention may be implemented in an optical storage disk mastering system to determine the position of mastering optics as the mastering optics translate over the surface of a storage master disk.
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.