Abstract: A hologram apparatus comprises a vibration detection beam generation unit to apply a vibration detection beam, incoherent to the data and reference beams and to detect the presence/absence of vibrations, to the hologram recording medium; a light reception/determination unit to receive the vibration detection beam emitted from the medium after the beam is applied to and propagates through the medium and to determine whether the beam receiving position is within a preset range; and an interruption unit to interrupt at least one of the data and reference beams from being applied to the medium, when this unit has determined that the position of beam reception is not within the preset range.

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: Embodiments of systems and methods are provided for a tunable laser device. The tunable laser device may include a tunable Bragg reflector that allows its wavelength to be tuned via temperature and/or pressure. This Bragg reflector may include holographic material in which a Bragg grating may be formed comprising parallel fringes of alternating index of refractions. Temperature and/or pressure changes may be effected in the Bragg reflector by, for example, a thermoelectric cooler and/or piezo transducer.

Abstract: Disclosed are mesophasic optical articles, methods of making mesophasic articles and methods of using mesophasic articles. In particular, this invention relates to mesophasic optical articles that can be prepared in situ with out the need of calcination, sintering, solvent evaporation, or other common method.

Abstract: A novel liquid photoreactive asymmetric acrylate compound containing sulfur, aromatic moieties, and optionally bromine, and having high dynamic range sensitivity is disclosed. The acrylate compound is a monomer for a photoimageable system. In one embodiment, when about 2–8% by weight of the acrylate compound is dissolved in a two-component urethane matrix system and incorporated in an optical article formed by reacting the two-component urethane matrix system, the optical article shows a sensitivity of about 4 or more and a shrinkage during the formation of the optical article of about 0.05% versus a sensitivity of 2.26 and a shrinkage of 0.13% when tribromophenyl acrylate, a commercial monomer, was used.

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: The present invention provides a method and system for increasing the holographic storage capacity of a holographic recording medium using an irradiance-tailoring (e.g., optical) element by changing the irradiance profile of the modulated object beam (e.g., by imparting motion to an irradiance-tailoring element and/or the holographic recording medium and/or by reconfiguring (e.g., periodically) the phase profile of a stationary irradiance-tailoring (e.g., optical) element) to minimize the effects of fixed-pattern noise buildup from occurring in the holographic recording medium.

Abstract: A holographic storage apparatus for recording data in a holographic medium includes at least one light source for generating a reference beam and a signal beam. The reference beam is preferably a phase beam of unchanging phase content. The apparatus also includes a holographic medium placed in a path of the reference beam and a path of the signal beam. The holographic medium has a first face and both the reference beam and the signal beam enter the holographic medium through the first face. The holographic medium also includes a data reflective surface. The reference beam and the signal beam interfere in the holographic medium to create a hologram only after at least one of the reference beam and the signal beam have reflected off of the data reflective surface.

Abstract: A method of determining coordinates for a storage medium includes: determining diffraction data from a plurality of diffraction patterns corresponding to diffractive markers of the medium; and combining the diffraction data to determine composite coordinates for the medium. The composite coordinates may include three translational coordinates and three rotational coordinates. The act of determining diffraction data may include shining a plurality of beams on a selection of the diffractive markers, and measuring the corresponding diffraction patterns in one or more photodetectors to determine the diffraction data. In this latter case the photodetectors may be segmented. The act of combining the diffraction data to determine composite coordinates may include solving a matrix system that couples the diffraction data and the composite coordinates. Each diffractive marker may include a pit. The storage medium may include a holographic storage medium.

Abstract: Disclosed are holographic storage systems and lenses for holographic storage systems. The lens units can be of a two-component design. The lenses can be used to both record to photorefractive storage media and to read from photorefractive storage media.

Abstract: The present invention relates to an article comprising: a pair of substrates comprising a thermoplastic; a holographic recording medium positioned between the substrates such that the holographic recording medium has at least one exposed area; and an environmental barrier seal protecting the at least one exposed area from environmental degradants; wherein the environmental barrier seal comprises: an inner layer adhered to at least one of the substrates and comprising a thermally meltable adhesive; an outer layer comprising a moisture impervious plastic; and an intermediate layer positioned between the inner and outer layers and comprising an moisture and oxygen impervious metallic foil. The present invention also provides a process for forming such an article.

Abstract: Disclosed is a multiplexing method and apparatus that allows holograms to be spatially multiplexed with partial spatial overlap between neighboring stacks of holograms. Each individual stack can additionally take full advantage of an alternate multiplexing scheme such as angle, wavelength, phase code, peristrophic, or fractal multiplexing, for example. An amount equal to the beam waist of the signal beam writing a hologram separates individual stacks of holograms. Upon reconstruction, a hologram and its neighbors will all be readout simultaneously. An filter is placed at the beam waist of the reconstructed data such that the neighbors that are read out are not transmitted to the camera plane. Alternatively, these unwanted reconstructions can be filtered out with an angular filter at an intermediate plane in the optical system that has a limited angular passband.

Abstract: Aspects of the present invention are generally directed to a holographic system. Generally, aspects of the present invention are directed to allocating power of a light beam generated by a coherent light source among the various discrete light beams used in a holographic system. Specifically, a variable optical divider is incorporated into an optical steering subsystem of the holographic memory system to redirect the coherent light beam into one or more discrete light beams, and to dynamically allocate power of the coherent light beam among the discrete light beams.

Abstract: The present invention relates to a system comprising a holographic data storage drive that records holographic digital data in a holographic recording medium, and which comprises: a data beam path having a first optical path length; and a reference beam path having a second optical path length; wherein one of the data beam and reference beams paths comprise an optical delay line so that the difference between the first and second optical path lengths is less than the laser coherence length. The present invention further relates to a method for operating a laser in the holographic data storage drive in a multi-mode state during the recording of holographic digital data the holographic medium without adverse effects on the strength of the interference patterns formed.

Abstract: The present invention relates to embodiments of a process for subjecting a holographic storage medium to illuminative treatment to: (1) enhance or optimize recording of holographic data; (2) enhance or optimize reading of recorded holographic data; and/or (3) erase recorded holographic data. The present invention also relates to embodiments of a system comprising: (a) an illuminative treatment beam; (b) means for reducing the coherence of the beam and (c) means for transmitting the reduced coherence beam to cause illuminative treatment of: (1) an unrecorded portion of a holographic storage medium to provide pre-cured portions having increased ability to stably record holographic data; (2) a recorded portion of a holographic storage medium to provide a post-cured portion having reduced residual sensitivity; and/or (3) a recorded portion of a holographic storage medium having holographic data to provide an erased portion wherein at least some of the recorded holographic data is erased.

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.

Abstract: A holographic memory system is disclosed. The holographic memory system comprises: a light source configured to generate a light beam; a photosensitive holographic storage medium configured to at least partially reflect the light beam; and an alignment module configured to determine an angular orientation of the storage medium based on the reflected light beam.

Abstract: The present invention relates to embodiments of a process for subjecting a holographic storage medium to illuminative treatment to: (1) enhance or optimize recording of holographic data; (2) enhance or optimize reading of recorded holographic data; and/or (3) erase recorded holographic data. The present invention also relates to embodiments of a system comprising: (a) an illuminative treatment beam; (b) means for reducing the coherence of the beam and (c) means for transmitting the reduced coherence beam to cause illuminative treatment of: (1) an unrecorded portion of a holographic storage medium to provide pre-cured portions having increased ability to stably record holographic data; (2) a recorded portion of a holographic storage medium to provide a post-cured portion having reduced residual sensitivity; and/or (3) a recorded portion of a holographic storage medium having holographic data to provide an erased portion wherein at least some of the recorded holographic data is erased.

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: Systems and methods are provided or use with a light source which generates a light beam. These systems may include a detector which detects light beam information and which determines whether multiple modes are present in the light beam so that the light source may be adjusted. These systems may further include a beam splitting device, such as an optical wedge, to provide two sample beams that intersect to provide a fringe pattern. The detector may then detect this fringe pattern and compute a visibility value that may be used to determine whether multiple modes are present.