Abstract: An efficient light coupling apparatus for interconnecting two optical components. Light radiation from the first optical component, for example an optical light fiber is directed onto the plane surface of the second optical component, for example a passive waveguide. The light is directed onto the second optical component at a convenient angle such that it impinges on the plane surface of the second optical component at an incident angle. An angularly selective coupling means, for example a volume hologram is located between the first and second optical components for coupling a maximum amount of the light at the incident angle.

Abstract: A waveguide hologram illumination system is based on thin substrate waveguides bearing a hologram on the surface through which light is diffracted out. A light source is optically coupled to the waveguide such that light emitted from the source is caused to propagate along the waveguide, being diffracted out at intersections with the surface of the waveguide on which the hologram is formed. The selective emission through the hologram can be advantageously used to illuminate display holograms or spatial light modulators. Provisions are made for rendering the amount of light emitted through the hologram uniform along the length of the hologram.

Abstract: A method and apparatus using a holographic storage medium for direct transmission of an optical image which can compensate for distortions occurring during transmission of the image.

Abstract: A hologram recording method wherein a transparent member for introducing a light beam into a recording material is designed so that the transparent member and the recording film can be uniformly brought into close contact with each other through an index matching liquid without damaging the recording film, and it is possible to stably carry out uniform and continuous exposure without failure of recording nor occurrence of unnecessary interference fringes. Also disclosed is a recorded hologram. A transparent member (3) is disposed at one surface of a recording film (2). A surface (5) of the transparent member (3) that is brought into close contact with the recording film (2) is convexly curved only in the direction of feed of the recording film (2). In addition, the space between the contact surface (5) and the recording film (2) is filled with an index matching liquid (4) so that the recording film (2) is brought into close contact with the transparent member (3) through the index matching liquid (4).

Abstract: In N.times.N optical couplers, such as are used in local area networks and backplanes of telecommunications and computer equipment, which use BRAGG volume diffraction means to couple light beams between the inputs and outputs, the number of gratings is reduced by means of so-called "grating degeneration" one grating can be shared by at least two wave pairs at the same time. In order to achieve this reduction, the directions of light waves in the dielectric slab (or the lateral positions of fibre ends) are suitable arranged. In other embodiments, a reduced number of gratings is achieved by using a "sandwiched" structure which uses multi-layered dielectric slabs. Both embodiments may be combined in the one coupler.

Abstract: A multimode waveguide having a small thickness has light coupled to the side of the waveguide in order to provide a multimode operation of the waveguide for providing a continuous pattern of totally internally reflected light which is utilized to reconstruct holographic images from a holographic emulsion placed on a surface of the waveguide. This waveguide structure for reconstructuring a hologram has the capability of providing highly efficient hologram reconstruction while using ordinary light sources and is able to use beam diameters greater than the thickness of the waveguide.

Abstract: A display hologram structure including a display hologram configured for reconstruction with a playback beam having a predetermined wavefront configuration, and a light configuring hologram that provides playback illumination for the display hologram pursuant to diffraction of an off-axis playback beam that does not have the predetermined wavefront configuration, and wherein the playback illumination provided by the light configuring hologram has the predetermined wavefront configuration.

Abstract: A method and apparatus for automatically providing for both multiplexing and independent external modulation of two or more wavelengths emitted by a multi-longitudinal mode laser. The present invention uses an integrated optics device chip to enable coupling of the dispersed wavelengths into separate electro-optic modulators which encode each of the carrier wavelengths with a different signal. Accordingly, the volume of data which can be transmitted over an optical fiber network is increased.

Abstract: A card-shaped waveguide-type image transmission device has an image transmission base member piled up on a light illumination base member, and an optical system such as grating patterns and diffraction lens pattern for diffracting and focusing light beams are formed on the surfaces of the image transmission base member and the light illumination base member. The card-shaped waveguide-type image transmission device is integrated with an ID card, an IC card, an optical card or a ROM card as a fingerprint identification device.

Abstract: Methods of recording and using holographic diffusers are disclosed for use with edge-lit backlight assemblies for transmissive flat-panel displays such as LCDs. When the holographic diffuser is supported against a surface of a backlight-emitting substrate it is operative to scatter the light in the direction of the display panel largely independent of angle of incidence. The recording methods may be used to produce both transmissive- and reflective-type diffusers, which may be employed simultaneously. In one embodiment a transmissive diffuser is used with a reflector and a cholesteric liquid crystal (CLC) polarizer. In this configuration, scatter lobes exhibiting the correct circular polarization are passed by CLC polarizer, whereas radiation of the opposite handedness is redirected toward the reflector, which converts the handedness into the form passable by the CLC polarizer.

Abstract: A method and apparatus for simultaneously exposing an optical fiber 32, made of a material which has a refractive index that can be permanently changed by exposure to light of a predetermined intensity at a predetermined wavelength, to two writing light beams 268,272 which intersect and interfere in a predetermined region 30 of the fiber 32 so as to create an interference pattern along a longitudinal axis of the fiber 32, for a time long enough to form a permanent refractive index variation in the waveguide. Each of said two writing beams have a predetermined number of wavelengths, each wavelength being sufficiently different from each other so as to cause said refractive index variation to be an aperiodic variation. Also, each wavelength represents a Fourier component of the desired aperiodic refractive index variation.

Abstract: A holographic apparatus for continually sensing, transmitting and reconstructing a three-dimensional image including a device for receiving a holographic interference pattern such as a video camera, a device for creating a holographic interference pattern on the receiving device, a device for focusing the interference pattern on the input of the receiving device, a device for transmitting the received holographic interference pattern including a device such as a computer, a device for converting the transmitted holographic interference pattern to a holographic interference pattern which is representative of the three-dimensional image such as an LCD and a source of coherent light illuminating the holographic interference pattern on the converting means to reconstruct the three-dimensional image.

Abstract: The present invention relates to an improved process for producing photorefractive net gain two beam coupling utilizing polymeric materials.

Abstract: An optical security system enables the integrity of a container seal to be remotely interrogated. A plurality of Bragg gratings is written holographically into the core of at least one optical fiber placed about the container seal, where each Bragg grating has a predetermined location and a known frequency for reflecting incident light. A time domain reflectometer is provided with a variable frequency light output that corresponds to the reflecting frequencies of the Bragg gratings to output a signal that is functionally related to the location and reflecting frequency of each of the Bragg gratings.

Abstract: A method and apparatus for making a holographic shadowgram of an object are disclosed. The method and apparatus include a light source for generating and expanding a coherent light beam. The method and apparatus also include a reflector for reflecting the coherent light beam to simultaneously produce a diffuse object beam and a coherent reference beam such that differential vibration between the object and reference beams is substantially eliminated, and for illuminating the object with the object beam and creating an interference pattern between the object and reference beams. The method and apparatus further include a recorder for recording the interference pattern to produce the holographic shadowgram.

Abstract: A portable holographic display system emboding holographic plates which are disposed upon a plurality of thin film holographic emulsions coupled to multiple channel Kerr units that generate a series of multi-colored holographic images. The holographic images generated by transmission thin film emulsions are based on the number and order that multiple light channels, fiber optics elements and thin film holographic emulsions are illuminated. The process of illumination depends directly on the activation sequence of lens elements or cells, which contain an optically active medium controlled by command signals from a central control means coupled to a source of electrical power.

Abstract: A method of fabricating diffraction gratings wherein a photomask is arranged on a substrate which is coated with a photoresist, light is to be incident thereupon at an acute angle relative to the normal direction of the photomask, and a bright/dark pattern is formed on said photoresist by the interference of the transmission light that has passed through the photomask and the diffraction light. The invention further deals with a photomask used for the above method.

Abstract: A waveguide holographic telltale display for displaying images to a vehicle driver via the vehicle windshield. A light source injects light into the base of a clear inner windshield singlet. A mirror hologram between the inner and outer singlets confines a majority of the injected light to the inner singlet. An image hologram between the windshield singlets diffracts light out to the vehicle driver. A halfwave plate between the image hologram and the inner singlet reduces ghosting and allows the driver to view the images even through polarized sunglasses. IR light is blocked by a tinted outer singlet or a holographic solar coating. The display does not suffer from ambient turn from the sun, and the light source is hidden away from the vehicle dash.

Abstract: A method of patterning an optical device for an optical IC whose purpose is to diffract a light beam incident on one surface of a device substrate to cause a light beam to emerge from another surface of the device. In this method, a layer of a substance of variable refractive index is formed on an optical substrate, coherent light is caused to irradiate the layer from the direction of the normal to the surface which will be the incidence side of the device when it is used or from the opposite side, and coherent light is caused to irradiate the layer from the direction of the normal to the surface which will be the emergence side of the device when it is used or from the opposite side to form an interference pattern on the layer that performs diffraction.

Abstract: A method of manufacturing a molded optical channel waveguide, having a critical internal reflection angle and an exposed surface, and affixing a holographic layer, having gratings formed therein, in overlying relationship with the exposed surface of the optical waveguide. The gratings are positioned to form an angle with the surfaces of the holographic layer such that light rays incident on an upper surface of the holographic layer and substantially normal thereto are diffracted by the gratings into the optical waveguide. Also, light waves travelling within the waveguide emanate outwardly through the holographic layer. Light generators and detectors are mounted to supply light to and receive light from the holographic layer.

Abstract: A multimode waveguide having a small thickness has light coupled to the side of the waveguide in order to provide a multimode operation of the waveguide for providing a continuous pattern of totally internally reflected light which is utilized to reconstruct holographic images from a holographic emulsion placed on a surface of the waveguide. This waveguide structure for reconstructuring a hologram has the capability of providing highly efficient hologram reconstruction while using ordinary light sources and is able to use beam diameters greater than the thickness of the waveguide.

Abstract: A method and apparatus for imaging an object that is part of, embedded in, or viewed through a scattering medium is provided. A broadband stochastic beam generator, such as a broadband laser, generates a broadband stochastic beam and a narrowband beam generator generates a narrowband beam. A non-linear mixing crystal receives the broadband stochastic beam and the narrowband beam and provides a signal light beam conjugate correlated with the broadband stochastic beam to the scattering medium. A multiple-wave mixing cell is disposed to receive the signal light beam from the scattering medium. An adjustable delay path also illuminates the multiple-wave mixing cell with the broadband stochastic beam. A supplemental beam generator is also provided for also additionally illuminating the multiple-wave mixing cell with a supplemental beam having characteristics sufficient to satisfy phase matching with the material of the multiple-wave mixing cell.

Abstract: A light-guiding device having a light-incident surface and a light-outgoing surface for guiding light incident from the light-incident surface from the light-outgoing surface toward a light-receiving surface of a photodetector for generating an electric signal corresponding to a quantity of the received light. The device comprises a hologram layer having an interference pattern which acts as a diffraction grating to diffract and reflect the light, incident from the light-incident surface, in a predetermined direction. The hologram layer is interposed between first and second total reflection layers.

Abstract: Separate features of a composite image in a field of view illuminated by a aser beam are respectively monitored by low level optical cavity resonators of an array from which optical data outputs are distributed to high level resonators for optical data correlation. Adjacent low level resonators of the array are coupled by controllers for modal interaction modified by feedback to the controllers from the high level resonators through optical signal transforming means for signal correction purposes in pattern recognition of the composite image.

Abstract: A holographic apparatus for continually sensing, transmitting and reconstructing a three-dimensional image including a device for receiving a holographic interference pattern, a device for creating a holographic interference pattern on the receiving device, a device for transmitting the received holographic interference pattern, a device for converting the transmitted holographic interference pattern to a holographic interference pattern which is representative of the three-dimensional image and a source of coherent light illuminating the holographic interference pattern on the converting means to reconstruct the three-dimensional image.

Abstract: A system for interconnection of a stack of circuit boards, wherein each of at least a plurality of the circuit boards has an end region carrying one or more light transmitters or light receivers, an optical structure forming an interconnecting backplane for the circuit boards, the optical structure comprising a first surface carrying a multiplicity of hologram elements disposed to receive light beams from said light transmitters and to route said light beams to a second reflective surface where said light beams are reflected back to said hologram elements for routing to said light receivers.

Abstract: A holographic objective system (3) produces an intermediate real image (4) of information displayed on an electrically addressable spatial light modulator or SLM (1), the real image (4) being collimated by a powered holographic reflector (5) constructed as part of the visor of a helmet worn by the viewer (9). The SLM (1) is illuminated by laser light from a remote laser (8) via a single optical fibre (6) and beam splitter (2). A diffuser (7) is provided either between the laser and the beam splitter or in the plane of the intermediate image (4). The objective system (3) may alternatively include, or consist entirely of, conventional optical elements.

Abstract: A compact, self-contained monolith hologram display apparatus includes a laser diode mounted on an edge of a solid glass plate having a front surface with a hologram mounted thereon. The beam is expanded within the glass plate and is reflected off an opposing mirrored contoured edge surface that collimates the beam and directs it onto an angled reflection grating. The reflection grating is mounted onto an edge which is canted with respect to the front surface. The reflected beam diffracts from the grating and impinges upon the hologram to provide for reconstructed image that has achromatic properties.

Abstract: A rod lens fixing method which can prevent the generation of cracks in a rod lens due to annealing to be carried out after welding a lens assembly. The rod lens fixing method includes the steps of providing a flanged split sleeve having an axial slit extending continuously from one end of the flanged split sleeve to the other end thereof, the axial slit being wide enough at least a flange of the flanged split sleeve to permit laser welding; press-fitting the rod lens into the flanged split sleeve; and applying a solder into the axial slit to solder the rod lens to the flange split sleeve. This method further includes the steps of inserting the flanged split sleeve into a bore formed at one end portion of a sleeve, the bore having a diameter larger than an outer diameter of the flanged split sleeve and smaller than an outer diameter of the flange; and laser-welding the flange to one end surface of the sleeve at a plurality of points on an outer circumference of the flange and in the axial slit.

Abstract: An apparatus for recording Lippman holographic mirrors comprises an exposing volume optically coupled on one side with an index-matching fluid to the holographic material to be recorded. The volume is exposed on an adjacent side to a light beam expanded in one direction into a plane of light whose projection on the volume is a line. The line of light and the holographic material are moved relative to each other on an interrupted or a continuous basis to expose the holographic material.

Abstract: An apparatus for interfacing holographic and electronic data comprises an input/output port for the interfacing of a holographic wavefront interference pattern and an electronic array capable of producing digital electronic information from a holographic wavefront input and for converting electronic information into holographic information using optical fibers, sensors, and optical switches. In one embodiment a plurality of optical fibers having a small end and a large tapered end are operably combined with a plurality of optical sensors wherein each of said optical sensors provide a digital signal of 1 if lit and a digital signal of 0 if unlit.

Abstract: A fiber optic point source is utilized to generate a first wavefront which is intersected with a second wavefront to form a desired interference pattern in a recording medium. The point source is moved relative to the recording medium during exposure in order to reduce multiple order scattering noise, and to provide a relatively large translational motion which is gradual and generally follows an angular scanning motion of the fiber optic point source.

Abstract: A fiber optic point source is utilized to generate a first wavefront which is intersected with a second wavefront to form a desired interference pattern in a recording medium. The point source is moved relative to the recording medium during exposure in order to reduce multiple order scattering noise, and a feedback monitoring system permits determination of portions of the recording medium requiring increased exposure.