Abstract: Holographic systems which shape coherent light beams are disclosed. These holographic systems may beam-shaping devices positioned in the path of coherent light beams to shape a coherent light beam into an essentially diffraction noise free coherent light beam of predetermined dimensions that has a continuous light beam profile of distinct intensity zones.

Abstract: The present invention relates to a system, as well as articles and holographic recording medium comprising the system, where the system comprises: a polymerizable component comprising at least one photoactive polymerizable material; and a photoinitiator component comprising at least one photoinitiator for causing the polymerizable component to polymerize to thereby form a plurality of holographic gratings when activated by exposure to a photoinitiating light source; wherein when a portion of the polymerizable component has been polymerized to form at least one holographic grating, the unpolymerized portion of the polymerizable component is resistant to further polymerization when not exposed to the photoinitiating light source. The present invention also provides methods for forming at least one holographic grating in a holographic recording medium having such a photopolymerizable system.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: A holographic recording medium having a polymer matrix comprising a developer, wherein the holographic recording medium is capable of recording a latent hologram and the developer is capable of developing the latent hologram into a readable hologram by activation of the developer is disclosed. The holographic recording medium is capable of storing large numbers of holograms in the same volume with better signal resolution than previous holographic media by first recording a multitude of latent (or very weak) holograms in the same volume of space, then applying preferably a non-chemical fixing step to develop the latent holograms into readable holograms. The holographic recording medium and method of this invention cause the holograms to increase in diffraction efficiency, thus preventing complications caused during recording of holograms whereby previously recorded holograms interfere with latter recorded holograms in the same volume of space within the media.

Abstract: In one aspect of the present invention, a device for sensing an absolute position of an encoded object, comprising: a position tracking module comprising: a track illumination module configured to illuminate the encoded object with one more light beams, and to detect one or more light beams resulting from said illumination of said encoded object; and an absolute position determinator configured to determine the absolute position of the encoded object based on said one or more light beams resulting from said illumination of said encoded object.

Abstract: An optical medium is provided. The optical medium comprises: a diffusion-controlling matrix framework; at least one photoactive monomer attached to the diffusion-controlling matrix framework in a first state of the optical medium, wherein the at least one photoactive monomer is released from the diffusion-controlling matrix framework by photo cleavage, producing a second state of the optical medium, in which diffusion of the photoactive monomer through the optical medium is possible; and wherein the at least one photoactive monomer is then polymerized or reattached to the diffusion-controlling matrix, giving a third state of the optical medium, when exposed to photo-polymerizing light.

Abstract: Systems and methods are provided for recovering data in a holographic memory system. One embodiment of these systems and methods uses homodyne detection to introduce a local oscillator beam into a reconstructed data beam of the recovered hologram. An image of the combined beam comprising the reconstructed data beam and local oscillator beam may be processed to obtain contrast level information for the pixels of the detected image. This contrast level information may then be used to obtain an increased contrast image of the recovered hologram, which may increase the SNR of the recovered data.

Abstract: An article with a pair of substrates made from a thermoplastic and each having an outer edge; a holographic storage medium positioned between the substrates such that the holographic storage medium has an exposed outer edge area proximate the outer edges of the substrates; and an environmental barrier seal protecting the exposed outer edge area; wherein (1) the environmental barrier seal includes a temperature-responsive stress-relieving structure; or (2) the substrates, holographic storage medium, and environmental barrier seal have materials with compatible coefficients of thermal expansion. Also a process which forms a temperature-responsive stress-relieving structure in a portion of the environmental barrier seal for relieving such temperature induced stress.

Abstract: A method is provided for manufacturing a holographic medium by recording holograms in transmission geometry, and applying a reflective layer to one side of the holographic recording material after recording is completed (alternatively, for example, the playback system may contain a reflective surface or mirror). For readout, the reference beam is incident to the media from a side opposite the reflective layer. This beam propagates through the media to the reflective layer on the opposite side, and is reflected back through the media for readout of the transmission hologram. The diffracted hologram signal also exits the media on the side without the reflective layer, where it can be recovered by a detector on the same side as the laser source. Alternatively, the readout reference beam is positioned so that the incident beam reads out the hologram, and both the reference beam and diffracted hologram are reflected back through the media.

Abstract: External cavity laser (ECL) systems and methods for measuring the wavelength of the ECL by using a portion of the positional light received by the position sensitive detector (PSD) to determine the position of a wavelength tuning element (such as a diffraction grating or an etalon), for determining the longitudinal laser mode or power output of the laser from a portion of the laser light received by a beam-shearing mode sensor, and by using a non-output beam(s) from a transmissive diffraction grating in the ECL to monitor the external cavity laser.

Abstract: In one aspect of the present invention, a device for sensing an absolute position of an encoded object, comprising: a position tracking module comprising: a track illumination module configured to illuminate the encoded object with one more light beams, and to detect one or more light beams resulting from said illumination of said encoded object; and an absolute position determinator configured to determine the absolute position of the encoded object based on said one or more light beams resulting from said illumination of said encoded object.

Abstract: Structures, subassemblies, devices, systems, and subsystems selected from: (1) a unitary holographic drive head assembly mounting structure; (2) an assembly including a unitary holographic drive head assembly mounting structure and a plurality of holographic drive head components and/or subassemblies; (3) a subassembly including a spatial light modulator, detector array, and a beam splitter; (4) a device including a spatial light modulator and a physical aperture positioned over or an imaged aperture projected onto the photoactive area of the spatial light modulator; (5) a system for optically aligning or pointing a laser in a holographic drive head assembly; (6) a light source subassembly including a laser, a fiber coupling lens; and an optical fiber having a fiber connector ready output end; and (7) a light source subsystem including a laser source, beam conditioning optics, fiber coupling optics for receiving the conditioned light beam, and a fiber optic connector for receiving the conditioned light beam f

Abstract: Systems and methods for recovering data in a holographic memory system. The systems and methods use homodyne detection to introduce a local oscillator beam into a reconstructed data beam of the recovered hologram. An image of the combined beam comprising the reconstructed data beam and local oscillator beam may be processed to obtain contrast level information for the pixels of the detected image. This contrast level information may then be used to obtain an increased contrast image of the recovered hologram, which may increase the SNR of the recovered data.

Abstract: Described are holographic storage mediums and method of making holographic storage mediums. The holographic storage mediums may have write components that bind to the matrix to form a pattern in the media. The holographic storage mediums may also be rewriteable.

Abstract: The present invention provides one or more books of holograms recorded in a recording medium, wherein two or more short stacks of the one or more books have locations that differ from each other by a movement difference. The present invention also provides methods and devices for recording and reading holograms from the one or more books of holograms.

Abstract: A method for adjusting at least one alignment control axis of a holographic data storage system or device to or towards a sufficiently optimal recovery position for recovery of a hologram based on a derived feedback error signal and/or a derived feed-forward signal. For the next hologram in the sequence, the derived feedback error signal estimates the direction and magnitude of misalignment of the at least one alignment control axis for one or more previously recovered holograms based on alignment-indicating data. The derived feed-forward signal estimates an optimal alignment value for the at least one alignment control axis for one or more holograms based on recording and recovery operating condition data for the holograms. An iterative alignment procedure may also be used to derive a feedback error signal for one hologram.

Abstract: The present invention relates to embodiments of: (1) a unitary holographic drive head assembly mounting structure; (2) an assembly comprising a unitary holographic drive head assembly mounting structure and a plurality of holographic drive head components and/or subassemblies; (3) a subassembly comprising a spatial light modulator, detector array, and a beam splitter; (4) a device comprising a spatial light modulator and a physical aperture positioned over or an imaged aperture projected onto the photoactive area of the spatial light modulator; (5) a system for optically aligning or pointing a laser in a holographic drive head assembly; (6) a light source subassembly comprising a laser, a fiber coupling lens; and an optical fiber having a fiber connector ready output end; and (7) a light source subsystem comprising a laser source, beam conditioning optics, fiber coupling optics for receiving the conditioned light beam, and a fiber optic connector for receiving the conditioned light beam from the fiber couplin

Abstract: To provide an optical recording apparatus capable of effectively suppressing useless fixation to an information-unrecorded area during a fixing process with a simple structure, and an optical head. Upon recording information, a movable lens of an expander lens 104 is positioned in an information recording position. In an information fixing process, the movable lens of the expander lens 104 is positioned in a fixing-process position. In this case, a range of irradiation to the recording medium with the data light becomes somewhat wider than that in the information recording process. Accordingly, it is possible to fix the information to an area irradiated with the data light in the information recording process without fail. In addition, the irradiation range is only somewhat wider than that in the information fixing process, making it possible to minimize the region uselessly subjected to the fixing process.

Abstract: The present invention provides a scanner comprising: a reflector component; means supporting the reflector component for pivoting with respect to the MCR to provide a scan which is stationary with respect to the OCR; means for enabling the support means to provide controlled pivoting of the reflector component; a magnet component which causes pivoting of the reflector component when actuated; and means for actuating the magnet component to thereby cause pivoting of the reflector component. Also provided is a scanner comprising a reflective prism for providing a circularized scanning beam, a prism carrier and magnet suspension assembly, and flexure means connected to the assembly to enable the prism to controllably pivot: (1) with respect to the MCR axis to provide a scan which is stationary with respect to the OCR; and (2) with respect to a pitch axis orthogonal to the MCR to provide an orthogonal scan.

Abstract: Methods and systems are provided for obtaining a phase conjugate reconstruction beam for use in retrieving holographic information from a holographic storage medium. These methods and systems include generating a coherent light beam that is a reproduction of the reference beam used in storing the holographic information in the storage medium. This coherent light beam is then directed through the holographic storage medium at the same angle and location of the reference beam during recording of the hologram. The directed coherent beam is then reflected back through the storage medium so that the reflected coherent light beam provides a phase conjugate of the reference beam and passes through the storage medium at the same angle and location that the reference beam passed through the storage medium during recordation of the hologram.