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: A matched amplification correlator transforms input images projecting a real time hologram upon a holographic storage device and a spatial light modulator, optically coupled to the storage device, modulates the hologram with a correlation filter, and the modulated signal is Fourier transformed to produce an output correlation signal. Alternatively, Fourier transforms of beams bearing the signals to be correlated are projected upon a beam controlled semi-conductor absorption modulator for selectively switching the Fourier transform of the noisy cluttered image through the device, and a spatial light modulator, modulates the hologram with a correlation filter, and the transform produces an output correlation signal. These compact adaptive, noise robust correlators can be made as small as one cubic centimeter. In a correlation system of exemplary figure one, nearly one hundred million correlations per second (0.1 Ghz) are possible. Front end components of the correlators can be used to clean noisy images.

Abstract: A single method and apparatus for producing many of the most common types of hologram from digital data is disclosed. In one embodiment the data are generated entirely by a computer as a 3-D (animated) model. In another embodiment the data are generated from multiple 2-D camera images taken of a real 3-D (moving) object or scene from a plurality of different camera positions. The data are digitally processed and displayed on a small high resolution spatial light modulator (SLM). A compact low energy pulsed laser, which avoids the usual vibration problems encountered at high rates of production and the installation in normal working environments, is used to record composite holograms on an holographic emulsion using a special optical design.

Abstract: A system for recording and reading out holograms in a storage medium comprising a pattern encoder, a first fourier transform lens with a focal length f1, a second fourier transform lens with a focal length f2, a detector array, and a first and second prism. The first prism is located between the pattern encoder and the first fourier transform lens, wherein the optical length between the pattern encoder and the first fourier transform lens through the first prism is equal to a back focal length BFL1. The second prism located between the second fourier transform lens f2 and the detector array, wherein the optical path length between the second fourier transform lens and the detector array through the second prism is equal to a back focal length BFL2.

Abstract: The invention presents the concept of self-referenced holographic data recording. In exemplary embodiments, the invention comprises methods of recording holograms on holographic data storage media; media produced by such methods; and self-referencing holographic data storage systems. A method of recording data in a holographic recording medium may comprise illuminating a medium with a data encoded first optical beam, optically directing a zero frequency Fourier component of the first optical beam to create a second optical beam, and illuminating the medium with the second optical. In some embodiments, for example, a self-referencing holographic data storage system has a single optical path directed towards a medium.

Abstract: An illumination panel for illuminating an object, comprising a substrate, a light diffractive grating and a light source. The substrate is made from an optically transparent material having first and second area surfaces disposed substantially parallel to each other and a light input surface for conducting a light beam into the substrate. The light diffractive grating is mounted to the first areal surface and has a slanted fringe structure embodied therein for diffracting the light beam falling incident thereto, along a first diffractive order of the slanted fringe structure. The light source produces a light beam for transmission through the input surface and direct passage through the substrate to the slanted fringe structure so as to produce an output light beam of areal extent that emerges from either the first or second areal surface along the first diffractive order, for use in illuminating an object.

Abstract: A Fourier hologram with the distribution of a radial harmonic function creates, in the far field, a pseudo non-diffracting beam. The properties of this pseudo non-diffracting beam can be set by appropriate characterization of the radial harmonic function. Various operations can also be carried out to change the position of the beam relative to the focal point. The beam can be shifted in space, twisted, or tilted.

Abstract: A system for projecting images is provided having a group of diffractive phase plates each encoded with different image information which have phase shifts aligned to reconstruct visible images in a Fraunhofer diffraction region. The plates are arranged along a path, and may represent successive frames of animation. A light source illuminates the plates and provides, when multiple plates are illuminated, a composite image representing image information encoded in such multiple plates. This composite image is a coincident superposition of reconstructed images from the multiple plates. A mechanism is provided for moving the plates along their path such that images projected from the system in the Fraunhofer diffraction region represent the composite image from successively different illuminated multiple plates or the reconstructed image from a single plate. Both monochromatic and multi-color channel phase plates may be used in the system.

Abstract: The invention presents the concept of self-referenced holographic data recording. In exemplary embodiments, the invention comprises methods of recording holograms on holographic data storage media; media produced by such methods; and self-referencing holographic data storage systems. A method of recording data in a holographic recording medium may comprise illuminating a medium with a data encoded first optical beam, optically directing a zero frequency Fourier component of the first optical beam to create a second optical beam, and illuminating the medium with the second optical. In some embodiments, for example, a self-referencing holographic data storage system has a single optical path directed towards a medium.

Abstract: A holographic microscope is described along with a method for numerically reconstructing a holographic image. The method uses a coordinate transformation of the Kirchhoff-Helmholtz equation to remove the non-linear component from the phase factor. The intensity distribution in the transformed coordinate system is then interpolated on an equidistant point grid and Fast-Fourier-Transforms are used to compute the result.

Abstract: Novel methods are disclosed for designing and constructing miniature optical systems and devices employing light diffractive optical elements (DOES) for modifying the size and shape of laser beams produced from a commercial-grade laser diodes, over an extended range hitherto unachievable using conventional techniques. The systems and devices of the present invention have uses in a wide range of applications, including laser scanning, optical-based information storage, medical and analytical instrumentation, and the like. In the illustrative embodiments, various techniques are disclosed for implementing the DOEs as holographic optical elements (HOEs), computer-generated holograms (CGHs), as well as other diffractive optical elements.

Abstract: A description is provided of an optical information recording and reproducing apparatus which detachably supports a volume holographic memory formed of a photorefractive crystal. The apparatus includes a portion for supplying a coherent reference light beam at a first wavelength into the volume holographic memory; a portion for supplying a coherent signal light beam at the first wavelength, modulated in accordance with image data, into the memory to produce an optical interference pattern with the reference light within the memory; a portion for supplying a gate light beam at a second wavelength into the memory for activating or deactivating an index grating in accordance with the presence or absence of the optical interference pattern to enhances a photo-sensitivity of the memory; and a detector for detecting diffraction light from the index grating of the memory by the irradiation of the reference light beam.

Abstract: A description is provided of an optical information recording and reproducing apparatus employing a holographic memory. The apparatus includes a mask disposed in an optical path of the signal light beam so as to cover a light intensity distribution of the signal light beam incident into the holographic memory at nearly a half portion thereof with respect to the center of the distribution of the zeroth-order diffracted light of the signal light beam. The center of a region of the holographic memory where the signal light beam and the reference light beam intersect with each other, is shifted by a distance substantially equal to twice the distance between peaks of the zeroth-order diffracted light or the first-order diffracted light of the signal light beam.

Abstract: A method and an apparatus capable of filtering based on desired spatial frequency characteristics without loss of Fourier spectrum frequency components, and of matched filtering of high recognition capability without losing functions of data recording and reconstruction as well as high-speed transmission and retrieval features and mass storage capacity characteristic of a holographic memory. Fourier transformed object light with 0° polarization of a target image is stored as a hologram using reference light having a spatial polarization distribution such that a daughter wavelet on scale m has 90° polarization. The hologram is retrieved using the Fourier transformed object light with 0° polarization. The hologram yields diffracted light in the form of a spatial frequency component which corresponds to scale m and is polarized 90° with respect to the other spatial frequency components. A polarizing element is used to extract only the spatial frequency component corresponding to scale m.

Abstract: Optical information processor and storage of pixelated data pattern in a Fourier plane of a lens as achieved by a plurality of optical elements operating with a spatial light modulator. A laser light source illuminates a data pattern with a wavefront that is created by a phase mask to effect a phase shift. The optical information can be effecitvely processed or stored, for instance, in a holographic data storage system. The holographic data storage system for storing a data array contains illuminated and dark regions including a multi-fold phase shift mask. This affects a linear and non-random shift of an image. The image is stored on a holographic storage medium. There is a spatial light modulator between the input location for the optical data and the storage medium. The phase shift is effected in the Fourier plane.

Abstract: Two pixel-oriented methods for designing Fourier transform holograms, pseudorandom encoding and minimum distance encoding when combined usually produce higher fidelity reconstructions than either method produces individually. In previous studies, minimum distance encoding was defined as the mapping from the desired complex value to the closest value produced by the modulator. This method is compared with a new minimum distance criterion in which the desired complex value is mapped to the closest value that can be realized by pseudorandom encoding. Simulations and experimental measurements using quantized phase and amplitude modulators show that the modified approach to blended encoding produces more faithful reconstructions than the previous method.

Abstract: Light emitted from a light source is split into a plurality of grating-like diverged beams of light by a Fourier transform phase hologram (3), and an image of a grating (100) is formed on a fiber (1) by a lens (4). Consequently, a grating cycle A can be obtained with accuracy ranging approximately from 25 to 1 (nm). Also, the grating cycle &Lgr; can be readily changed.

Abstract: A method for the numerical reconstruction of digital holograms which allows simultaneously amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the field that would be diffracted by the hologram during a standard hologram reconstruction. The method requires the adjustment of several reconstruction parameters for the definition of a digital replica of the reference wave. When the set-up used for the hologram creation produces phase aberrations, the method includes a digital method for the correction of the phase aberrations. The phase contrast image is quantitative, meaning that the reconstructed phase distribution can be used for quantitative measurements. The method can be used to reconstruct a set of holograms taken in different conditions. The method can be used to reconstruct several images from a single hologram taken with more than one reference waves and/or more than one object waves.

Abstract: A planar optical correlator including at least first and second optical substrates (30, 32), through which light propagates by means of total internal reflection, at least first and second holographic lenses (20, 22) on the first optical substrate and optical third and fourth holographic lenses (24, 26) on the second optical substrate, each of the first and second and third and fourth holographic lenses performing a Fourier transformation on the input light to their respective optical substrates, the substrates positioned such that the second and third holographic lenses at least partially face each other. A filter (36) is positioned between the second and third holographic lenses.

Abstract: 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.

Abstract: A holographic grating is written into a photorefractive erasable holographic member and a light beam having a first wavelength which includes the joint power spectrum of a pair of joint images to be correlated is directed at the photorefractive member to partially erase the grating. A phase conjugate signal from the partially erased grating is then readout and Fourier transformed to produce the correlation output spots.

Abstract: A holographic memory system which utilizes the Talbot Effect for the lensless, near-field propagation of repeating image planes of periodic structures. Periodic phase structures at one plane in a holographic memory system are mapped to the input amplitude data plane in the holographic memory system. In a preferred embodiment, coherent light is passed through a lenslet array and propagated via the Talbot Effect to self-image coincident on a spatial light modulator that provides the holographic memory system with input data. The lenslet array is located relative to the spatial light modulator such that the desirable phase image structure is self-imaged in its Fresnel region onto the input amplitude data structure.

Abstract: A holographic storage and retrieval system for use in co-propagating or counter-propagating geometries having a common optical relay for guiding a signal beam and a reference beam along a common optical axis to a holographic medium to write a hologram therein. The optical relay has an object region imaging quality such that at least 65% and preferably at least 80% of the nominal luminous energy from object pixels is encompassed or "ensquared" by the corresponding image pixels. Additionally, the optical relay has a high total numerical aperture (N.A.) of about 0.83, a pixel N.A. of approximately 0.04 for the signal beam. The system of the invention can be used with holographic storage media in the form of disks, tapes or bulk holographic crystals.

Abstract: A constituent unit for an optical information processing system comprises an input information displaying device, which one-dimensionally, two-dimensionally, or three-dimensionally displays presented information as an optical pattern. Each of optical correlation operation devices located close to the input information displaying device detects only an optical pattern falling within a predetermined range among the optical pattern displayed on the input information displaying device, and carries out an optical correlation operation in order to calculate correlation between information representing the detected optical pattern and predetermined information having been stored in each optical correlation operation device. Each optical correlation operation device thereafter feeds out the results of the correlation operation.

Abstract: The laser transfer machining apparatus comprises a shaping unit for shaping the laser beam so that the laser beam has a beam pattern which corresponds to a desired pattern to be machined in the object to be machined and a generating unit disposed separately from the shaping unit for simultaneously generating a plurality of laser beams each having the beam pattern from the laser beam shaped by the shaping unit. The generating unit is adapted to emit the plural laser beams while simultaneously defining a plurality of radiation directions of the generated plural laser beams to the object to be machined. The laser transfer machining apparatus can provide a high efficiency of utilization of light and reduce the time required for machining. Furthermore, the laser transfer machining apparatus can utilize a laser with a relatively low spatially coherence such as an eximer laser.

Abstract: A real time fingerprint verification system includes a recording device and a verification device each having a fingerprint scanner for generating a flat, dimensionally undistorted, high contrast, fingerprint image, and an intensity sensitive, spatial light modulator (SLM) for receiving and transforming the flat fingerprint image into a planar, coherent light image. In the recording device, the planar coherent light image beam of the fingerprint from the SLM is Fourier transformed, and input into a microscope objective lens system which expands the Fourier transformed beam image sufficiently to allow mechanical blocking of its central portion or order, whereupon it is directed to interact as an object beam with a reference beam from the particular coherent light source to record a holographic matched filter.

Abstract: The present invention provides a method for producing double-card anti-counterfeit marks with interlock protection based on the technique which combines nuclear technology with computer-generated hologram (CGH) technology and inspecting apparatus for the mark. The invention relates to the technical field of optical information processing in physics. The technical feature of the invention is to insert potential images R,T and matched potential images R',T' in the anti-counterfeit identification marks and in the inspecting identification marks respectively by means of charged particle track image in sampling coincidence with CGH. When R coincides with R', a certain message of genuineness for an identification mark will be shown, and when T coincides with T', different specific information in thousands of ways appears to prove the genuineness of the protected objects.

Abstract: A method and apparatus of encrypting optical images and storing these images in memory using random phase encoding is presented. The encryption technique uses random phase encoding in both the input plane and the Fourier plane. Each image is encrypted and can be read out by a unique code or a universal code. The image to be encrypted is first multiplied by a random phase function. The Fourier transform of the product of the image and the random phase function is then multiplied by another random phase function in the Fourier domain. Taking the inverse Fourier transform, an encrypted image in the output plane is obtained. Each encrypted image can be stored in optical memory. The encryption process of the present invention can be done optically or electronically with one or two dimensional functions for encryption. Further, the image can be phase encoded (optically or digitally) prior to the encryption process, with a phase reading technique employed to obtain the original decrypted image.

Abstract: A holographic data storage apparatus having no readout lens. The apparatus has a spatial light modulator (SLM), a focusing element such as a lens, a holographic data storage material and a spatial light detector such as a CCD. The lens is located between the SLM and CCD such that the SLM is imaged onto the CCD (i.e. the positions of the SLM, lens, and CCD satisfy the lens equation). The holographic storage material is located between the lens and CCD. Preferably, the storage material is located centered upon a Fourier plane of the lens. In this case, the apparatus also has a phase mask located adjacent to the SLM. Alternatively, the storage material is located a distance away from the Fourier plane or is not centered on the Fourier plane. In yet another embodiment, the holographic storage material is located in contact with the CCD.

Abstract: The present invention is a holographic reconstruction device for reconstructing successive holograms previously recorded by a recording reference beam in a recording medium, each previously recorded successive hologram being spaced apart a recording displacement. The recording reference beam has a recording wavelength in the range where the recording medium is photosensitive and a recording propagation angle. The device comprises a reconstruction mechanism having a reconstruction reference beam with a reconstruction wavelength in the range where the recording medium is relatively photo-insensitive and a reconstruction propagation angle. The reconstruction reference beam is provided onto the recording medium. Also, a succession of relative displacements in the recording medium is produced and each of the displacements are equal to the distance of the recording displacements with which the holograms were previously recorded.

Abstract: A superresolution scanning optical device has image forming means for forming the image of light from a coherent light source unit in the form of a fine spot on a conjugate face through an image forming optical system, and scanning means for scanning the fine spot formed on the conjugate face. The coherent light source unit has first and second light sources of which phases are reverse to each other. The first and second light sources have the relationship that the main lobe of the image of the second light source on the conjugate face is superposed on the lateral sides of the main lobe of the image of the first light source on the conjugate face.

Abstract: An optical demultiplexing apparatus is capable of spatially separating a multiplexed optical signal into two or more optical wavelength signals thereof. An input multiplexed optical signal present on a first plane is imaged through a color-selective grating plane to a second plane. The color-selective grating has a nonlinear change of diffraction characteristics as a function of incident wavelength to provide substantial spatial separation in the second plane between bands of wavelengths proximate to the two or more optical wavelength signals. In another embodiment, the apparatus uses a polarization-selective grating to spatially separate a polarization-multiplexed optical signal into two substantial spatially separated optical polarization signals. In other embodiments, the optical apparatus may be used as an optical signal multiplexer, splitter, or combiner.

Abstract: A light source for use in an infra-red data association data link device including a vertical cavity surface emitting laser for emitting a beam of light along a path, and a diverger positioned in the path for diverging the emitted beam of light.

Abstract: A method for improving the resolution and contrast of images associated with coherent recording is presented, which includes conventional reconstruction with a reference wave followed by re-imaging the intermediately formed image through a system based on techniques from confocal microscopy. This method provides the opportunity to bring the benefits of the optical confocal microscope, namely resolution, contrast improvement, and the accompanying three-dimensional visualization, to such diverse imaging regimes as infrared, X-ray, ultraviolet, as well as other wave propagation systems such as seismic, sonar and ultrasound imaging. In addition, through snap-shot acquisition of said coherent recordings, the capability of time resolution may be added, thus adding functionality in wavelength regions where the confocal microscope currently operates.

Abstract: A method and apparatus of encrypting optical images and storing these images in memory using random phase encoding is presented. The encryption technique uses random phase encoding in both the input plane and the Fourier plane. Each image is encrypted and can be read out by a unique code or a universal code. The image to be encrypted is first multiplied by a random phase function. The Fourier transform of the product of the image and the random phase function is then multiplied by another random phase function in the Fourier domain. Taking the inverse Fourier transform, an encrypted image in the output plane is obtained. Each encrypted image can be stored in optical memory. The encryption process of the present invention can be done optically or electronically with one or two dimensional functions for encryption. Further, the image can be phase encoded (optically or digitally) prior to the encryption process, with a phase reading technique employed to obtain the original decrypted image.

Abstract: An all optical photorefractive holographic joint transform correlator provides a first correlation plane output port using two-beam coupling, and a second correlation plane output port employing four-wave mixing. With appropriate input beam intensity ratios, the first port output is capable of high discrimination, while simultaneously the second port offers a low discrimination output.

Abstract: A method for the production of holograms proof against copying and imitation possessing authenticity features, which are copies of a master hologram. In accordance with the invention as a master hologram a hologram of a randomly structured optical element, as for example a diffusion plate, which constitutes the authenticity feature, is recorded and each hologram copy produced from the master hologram is provided with a layer having at least one layer with a color succession and/or the hologram copy produced on a thick light sensitive layer is caused to shrink or to expand.

Abstract: Use of an aperture in the reconstructed beam in reconstruction of multiple holograms increases selectivity beyond that realizable by spatial multiplexing so as to permit differentiation of overlapping images. "Aperturization" is suitably used for differentiation in the y-direction in shift holography, depending on Bragg selection in the x-direction.

Abstract: An information carrier has at least one diffraction pattern which is formed from microscopically fine relief structures and which, upon being illuminated with coherent light, produces in two spatially separate directions, a first and a second image of an object. The images can be rendered visible on a screen or analysed by means of photodetectors. The two images have strong-light and/or weak-light picture elements and includes a symmetry insofar as a weak-light picture element of the second image can be associated with a strong-light picture element of the first image and vice-versa. Such information carriers are suitable as security elements for documents of all kinds such as, for example, banknotes, passes, identity cards, credit cards, etc., wherein at least a part of the security information is not visible under incoherent illumination conditions.

Abstract: A module, capable of being mounted on a printed circuit board, containing optical components necessary for optical correlation and a unique folded light path technique for conversion from a Vander Lugt optical correlator to a joint-transform optical correlator, or visa versa, with no electronic changes required. The folded optical path permits a polarizing filter to be positioned in the beam path reflected by a filter SLM but before a correlation detector means when the correlator is in a Vander Lugt mode and permits the polarizing filter to be removed, and an auxilliary mirror or other optical components positioned in the beam path to eliminate the filter SLM and to direct the beam path toward the correlation detector means when the optical correlator is to become a two-cycle joint-transform optical correlator and simultaneously match the Fourier transform plane to the detector plane of the detector means.

Abstract: 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.

Abstract: The invention is directed to an information-recorded medium with easily selectable and identifiable items of information, which is virtually protected against forgery and has enhanced security against some improper use, and a method for reading such a medium. This information-recorded medium 1 includes a substrate 2 and a layer 3 with information recorded thereon by the printing of infrared absorbing ink, said layer 3 being provided on the surface of the layer 2. The printed layer 3 is provided thereon with a relief hologram-recorded layer 7 through an adhesive layer 4, said hologram-recorded layer 7 being built up of a reflecting layer 5 transparent to the infrared region and a relief hologram-formed layer 6 provided on the surface of the reflecting layer 5. For reading, the hologram-recorded layer 7 is reconstructed by visible light, while the printed layer is reconstructed by infrared light, and the medium 1 is identified on the basis of the thus reconstructed information.

Abstract: 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.

Abstract: A method for the production of holograms proof against copying and imitation possessing authenticity features, which are copies of a master hologram. In accordance with the invention as a master hologram a hologram of a randomly structured optical element, as for example a diffusion plate, which constitutes the authenticity feature, is recorded and each hologram copy produced from the master hologram is provided with a layer having at least one layer with a color succession and/or the hologram copy produced on a thick light sensitive layer is caused to shrink or to expand.

Abstract: 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.

Abstract: N lines of line-shaped light are projected onto the object by means of a measuring light projecting lens. The light carrying the image of the object is passed through the eyepiece lens 17 in an endoscope 6 and the auxiliary lens 30 in a measuring head 11 and split into two beamlets by a beam splitter 31, with one beamlet being focused at a position coinciding with the entrance end faces of measuring light's position detecting fibers 33(l) to 33(m). The line-shaped light images of the object thus formed in positions coinciding with the entrance end faces of measuring light's position detecting fibers 33(l) to 33(m) are scanned linearly by those linearly aligned fibers as they are oscillated and driven by a fiber scanner 36. The scanned line-shaped light images are then subjected to the necessary signal processing in a signal processor circuit 35 such as to measure the three-dimensional configuration of the object.

Abstract: A holographic stereogram which includes a plurality of element holograms and which reproduces a stereoscopic image by irradiation of coherent light, wherein each element hologram is loaded with a modulation value (pattern) corresponding to the stereoscopic image, the modulation value being a one-dimensional or two-dimensional transform coefficient obtained by one-dimensional or two-dimensional cosine transform or discrete cosine transform of the distribution of the intensity of diffraction light expressing the stereoscopic image, enabling simplification of the drive system of the display device displaying the stereoscopic image and reproduction of the original stereoscopic image much more faithfully.

Abstract: A method is provided for normalizing correlation data from a holographic correlator. After a sequence of object image patterns are recorded in an angularly multiplexed hologram, the entire volume hologram contents are read out with a uniform (plane wave) object beam. The plane wave readout produces an array of spots at a correlation plane, with the intensity of each spot representing the strength of the recorded hologram for the corresponding stored image pattern. The spot intensity values are accurately detected and stored as normalization factors. Holographic correlation output array values produced by parallel comparison of an input object pattern with the stored image patterns are then divided by the corresponding normalization factors. The resulting normalized correlation output accurately represents the true degree of correlation between the input object pattern and the stored image patterns by eliminating the uncertainty factor.

Abstract: The invention is embodied in a method of recording successive holograms in a recording medium, using at least a fan of M waves along at least a first axis with a separation angle between adjacent waves and directing the fan of M waves as a reference beam along a reference beam path onto the recording medium, successively modulating a wave with a succession of images to produce a succession of signal beams along a signal beam path lying at a propagation angle relative to the reference beam path so that the signal and reference beams intersect at a beam intersection lying within the medium, the beam intersection having a size corresponding to beam areas of the reference and signal beams, producing a succession of relative displacements in a direction parallel to the first axis between the recording medium and the beam intersection of the signal and reference beam paths in synchronism with the succession of signal beams, each of the displacements being less than the size of the intersection whereby to record suc

Abstract: An apparatus and method are disclosed for providing holographic matched filters for application in all-optical holographic processing of ultrahigh-speed optical data. A scaled spatial image of temporal-domain data is provided by a spatial light modulator (SLM). The scaled image of the SLM is read out with a single-mode diode laser and transformed into a wavelength spectrum by a Fourier transform lens. The interference fringe patterns between the spectrum of the scaled spatial data pattern and the reference pattern beam are recorded by a holographic recording medium. Alternatively, the scaled spatial image of the temporal data is fixed in an aperture mask. An apparatus and method are also disclosed for decoding high-speed optical signal packet headers using holographic matched filters.