Lucent Technologies Inc.

Michael C Tackitt

Kevin R Curtis

Scott Patrick Campbell

Thomas J Richardson

Partha Pratim Mitra

Clifford Eric Martin

Peter M Winkler

Adrian John Hill

Apparatus for holographic recording of information includes a lens or lens system, referred to here as the &ldquo;FT lens,&rdquo; situated in such a way that light from an object beam enters the FT lens after passing through an object, and light leaving the FT lens impinges on a recording medium situated at a Fourier transform plane of the object with respect to the FT lens. Disclosed apparatus includes a phase element effectively juxtaposed with the object, in which the phase element is effective for redistributing object-beam intensity in the Fourier transform plane, and the phase element has a correlation length greater than a maximum pixel side length associated with the object. Disclosed apparatus includes an optical element or optical system, referred to here as a &ldquo;power optic,&rdquo; that adds convergence or divergence to the object beam before the object beam enters the FT lens.

Method and apparatus for holographic data storage

The invention relates to a skip-sorted spatial multiplexing holographic storage technique that addresses the problems of cross-talk, image distortions, and physical change of the medium encountered in current recording processes in which photopolymer media are used. The skip-sorted technique involves storing holograms in layers of arrays, such that a substantially uniform background exposure is provided for subsequent layers.

Process for holography involving skip-sorted hologram storage

The invention involves a holographic system containing a photopolymer-type storage medium located in the system's optical path, where the medium is rotated around a first axis such that the surface of the medium is in a non-orthogonal relationship with the optical path, and a spatial light modulator also located in the optical path, where the modulator is rotated around a second axis that is substantially orthogonal to the first axis, and wherein the surface of the modulator is in a non-orthogonal relationship with the optical path. This arrangement compensates for at least a portion of aberration introduced by the photopolymer media, thereby allowing presentation of a flatter, more focused, and less distorted image at the sensor.

Process for holography involving tilt compensation

We disclose apparatus for holographic recording of information. The apparatus includes a lens or lens system, referred to here as the 'FT lens,' situated in such a way that light from an object beam enters the FT lens after passing through an object, and light leaving the FT lens impinges on a recording medium situated at a Fourier transform plane of the object with respect to the FT lens. In certain aspects of the invention, the apparatus includes a phase element effectively juxtaposed with the object, the phase element is effective for redistributing object-beam intensity in the Fourier transform plane, and the phase element has a correlation length greater than a maximum pixel side length associated with the object. In certain other aspects of the invention, the apparatus includes an optical element or optical system, referred to here as a 'power optic,' that adds convergence or divergence to the object beam before the object beam enters the FT lens.

Systems and methods for steering a complex, spatially-modulated incident beam of coherent light to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a reflective element, locatable proximate a first focal plane of the incident beam, (2) a rotational steering mechanism, coupled to the reflective element, that orients the reflective element according to a desired rotational angle to steer the incident beam in a desired direction and (3) a refractive element that refracts the beam reflected from the reflective element to create a second focal plane for the beam, the HMC locatable proximate the second focal plane to receive the beam at a location thereon that is a function of the desired direction.

System and method for steering focal plane data to access data locations

Systems and methods for steering an optical path to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) first and second reflective elements locatable to receive and reflect a complex, spatially-modulated incident beam of light, (2) a reflective element steering mechanism, coupled to the first and second reflective elements, that moves the first and second reflective elements to steer the incident beam in a desired direction and (3) an HMC rotating mechanism, couplable to the HMC, that rotates the HMC about an axis thereof, the reflective element steering mechanism and the HMC rotating mechanism cooperating to cause the incident beam to illuminate a location on a plane of the HMC that is a function of a movement of the first and second reflective elements and a rotational position of the HMC.

System and method for steering Fresnel region data using cylindrical

Systems and methods for steering an optical path to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a refractive element that receives a complex, spatially-modulated incident beam of light, (2) first and second reflective elements locatable to receive and reflect the incident beam in a Fresnel region thereof and (3) a reflective element steering mechanism, coupled to the first and second reflective elements, that moves the first and second reflective elements in tandem to steer the incident beam with respect to the HMC thereby to cause the incident beam to illuminate a location on the HMC that is a function of a movement of the first and second reflective elements.

System and method for steering fresnel region data to access data

Systems and methods for steering a complex, spatially-modulated incident beam of light from a spatial light modulator to gain access to data locations in a holographic memory cell (HMC). One of the systems includes (1) a primary beam steering system that receives the incident beam of light from the spatial light modulator and produces a resulting beam of light, wherein the primary beam steering system traverses the resulting beam of light across a plane of the HMC in increments having a first magnitude and 2) a fine-control translation mechanism, coupled to the spatial light modulator, that translates the spatial light modulator relative to the primary beam steering system to cause the resulting beam of light to traverse the plane of the HMC in increments having a second magnitude smaller than the first magnitude.

System and method using linear translation to access data locations in a

A method for processing information stored in a holographic system, comprising the step of intersecting a reconstruction reference beam with a storage medium of a holographic system, the storage medium exhibiting birefringence at least partially due to coherent storage of information, wherein the reconstruction reference beam has a polarization at least 5.degree. different from the polarization exhibited by a storage reference beam during storage information in the storage medium.

Method for processing information stored in a holographic system

Systems and methods for steering a complex, spatially-modulated incident beam of coherent light to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a reflective element, locatable proximate a first focal plane of the incident beam, (2) a rotational steering mechanism, coupled to the reflective element, that orients the reflective element according to a desired rotational angle to steer the incident beam in a desired direction and (3) a refractive element that refracts the beam reflected from the reflective element to create a second focal plane for the beam, the HMC locatable proximate the second focal plane and rotatable about an axis of a plane thereof to receive the beam at a location thereon that is a function of the desired direction and an angular position of the HMC.

System and method for steering focal plane data using cylindrical

Systems and methods for steering an optical path to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a reflective element, locatable proximate a first focal plane of a complex, spatially-modulated incident beam of light, (2) a polar steering mechanism, coupled to the reflective element, that orients the reflective element according to desired tilt and precession angles to steer the incident beam in a desired direction and (3) a refractive element that refracts the beam reflected from the reflective element to create a second focal plane for the beam, the HMC locatable proximate the second focal plane to receive the beam at a location thereon that is a function of the desired direction.

System and method for precessing an optical path using cylindrical

Bit error rate in holographic storage/reconstruction is reduced by 2-dimensionally dispersing symbols constituting codewords so that no two codeword-common symbols occupy a single row or column on the SLM display.

Holographic storage of digital data

Bit error rate of an output data stream, reconstructed from a holographic recording, is reduced by reducing the length of same-state pixels on the spatial light modulator.

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Califon, NJ, United States of America

Michael C Tackitt